Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| molecular signals required for type iii secretion and translocation of the xanthomonas campestris avrbs2 protein to pepper plants. | strains of xanthomonas campestris pv. vesicatoria (xcv) carrying avrbs2 are specifically recognized by bs2 pepper plants, resulting in localized cell death and plant resistance. agrobacterium-mediated transient expression of the xcv avrbs2 gene in plant cells results in bs2-dependent cell death, indicating that the avrbs2 protein alone is sufficient for the activation of disease resistance-mediated cell death in planta. we now provide evidence that avrbs2 is secreted from xcv and that secretion ... | 2000 | 11078519 |
| biological role of xanthomonadin pigments in xanthomonas campestris pv. campestris. | previous studies have indicated that the yellow pigments (xanthomonadins) produced by phytopathogenic xanthomonas bacteria are unimportant during pathogenesis but may be important for protection against photobiological damage. we used a xanthomonas campestris pv. campestris parent strain, single-site transposon insertion mutant strains, and chromosomally restored mutant strains to define the biological role of xanthomonadins. although xanthomonadin mutant strains were comparable to the parent st ... | 2000 | 11097878 |
| fatty acid competition as a mechanism by which enterobacter cloacae suppresses pythium ultimum sporangium germination and damping-off. | interactions between plant-associated microorganisms play important roles in suppressing plant diseases and enhancing plant growth and development. while competition between plant-associated bacteria and plant pathogens has long been thought to be an important means of suppressing plant diseases microbiologically, unequivocal evidence supporting such a mechanism has been lacking. we present evidence here that competition for plant-derived unsaturated long-chain fatty acids between the biological ... | 2000 | 11097912 |
| quorum sensing in vibrio fischeri: analysis of the luxr dna binding region by alanine-scanning mutagenesis. | luxr is the transcriptional activator for quorum-sensing control of luminescence in vibrio fischeri. a series of alanine-scanning mutants spanning a predicted helix-turn-helix region in the dna binding domain of luxr was constructed, and the activity of each of the luxr mutant proteins in recombinant escherichia coli was investigated. the region covered by the mutagenesis spanned residues 190 to 224. about half of the alanine-scanning mutants showed activities similar to that of the wild-type lu ... | 2001 | 11114939 |
| transcriptional regulation of transport and utilization systems for hexuronides, hexuronates and hexonates in gamma purple bacteria. | the comparative approach is a powerful tool for the analysis of gene regulation in bacterial genomes. it can be applied to the analysis of regulons that have been studied experimentally as well as that of regulons for which no known regulatory sites are available. it is assumed that the set of co-regulated genes and the regulatory signal itself are conserved in related genomes. here, we use genomic comparisons to study the regulation of transport and utilization systems for sugar acids in gamma ... | 2000 | 11115104 |
| cloning and characterization of thermostable endoglucanase (cel8y) from the hyperthermophilic aquifex aeolicus vf5. | aquifex aeolicus is the hyperthermophilic bacterium known, with growth-temperature maxima near 95 degrees c. the cel8y gene, encoding a thermostable endoglucanase (cel8y) from aquifex aeolicus vf5, was cloned into a vector for expression and expressed in escherichia coli xl1-blue. a clone of 1.7 kb fragment containing endoglucanase activity, designated pkycy100, was sequenced and found to contain an orf of 978 bp encoding a protein of 325 amino acid residues, with a calculated molecular mass of ... | 2000 | 11118302 |
| characterization of vibrio cholerae o1 el tor galu and gale mutants: influence on lipopolysaccharide structure, colonization, and biofilm formation. | recently we described the isolation of spontaneous bacteriophage k139-resistant vibrio cholerae o1 el tor mutants. in this study, we identified phage-resistant isolates with intact o antigen but altered core oligosaccharide which were also affected in galactose catabolism; this strains have mutations in the galu gene. we inactivated another gal gene, gale, and the mutant was also found to be defective in the catabolism of exogenous galactose but synthesized an apparently normal lipopolysaccharid ... | 2001 | 11119535 |
| gene integration and expression and extracellular secretion of erwinia chrysanthemi endoglucanase cely (cely) and celz (celz) in ethanologenic klebsiella oxytoca p2. | the development of methods to reduce costs associated with the solubilization of cellulose is essential for the utilization of lignocellulose as a renewable feedstock for fuels and chemicals. one promising approach is the genetic engineering of ethanol-producing microorganisms that also produce cellulase enzymes during fermentation. by starting with an ethanologenic derivative (strain p2) of klebsiella oxytoca m5a1 with the native ability to metabolize cellobiose, the need for supplemental beta- ... | 2001 | 11133422 |
| cloning and characterization of a periplasmic nuclease of vibrio vulnificus and its role in preventing uptake of foreign dna. | we have cloned a nuclease gene, vvn, from vibrio vulnificus, an estuarine bacterium that causes wound infections and septicemia in humans and eels. the gene contained a 696-bp open reading frame encoding 232 amino acids (aa), including a signal sequence of 18 aa. the deduced amino acid sequence of the mature nuclease predicted a molecular mass of 25 kda, which was confirmed by vital stain, and a pi of 8.6. vvn was produced in the periplasm of either v. vulnificus or recombinant escherichia coli ... | 2001 | 11133431 |
| direct cloning from enrichment cultures, a reliable strategy for isolation of complete operons and genes from microbial consortia. | enrichment cultures of microbial consortia enable the diverse metabolic and catabolic activities of these populations to be studied on a molecular level and to be explored as potential sources for biotechnology processes. we have used a combined approach of enrichment culture and direct cloning to construct cosmid libraries with large (>30-kb) inserts from microbial consortia. enrichment cultures were inoculated with samples from five environments, and high amounts of avidin were added to the cu ... | 2001 | 11133432 |
| pantoea agglomerans strain eh318 produces two antibiotics that inhibit erwinia amylovora in vitro. | pantoea agglomerans (synonym: erwinia herbicola) strain eh318 produces through antibiosis a complex zone of inhibited growth in an overlay seeded with erwinia amylovora, the causal agent of fire blight. this zone is caused by two antibiotics, named pantocin a and b. using a genomic library of eh318, two cosmids, pcpp702 and pcpp704, were identified that conferred on escherichia coli the ability to inhibit growth of e. amylovora. the two cosmids conferred different antibiotic activities on e. col ... | 2001 | 11133457 |
| involvement of the xpsn protein in formation of the xpsl-xpsm complex in xanthomonas campestris pv. campestris type ii secretion apparatus. | the xps gene cluster is required for the second step of type ii protein secretion in xanthomonas campestris pv. campestris. deletion of the entire gene cluster caused accumulation of secreted proteins in the periplasm. by analyzing protein abundance in the chromosomal mutant strains, we observed mutual dependence for normal steady-state levels between the xpsl and the xpsm proteins. the xpsl protein was undetectable in total lysate prepared from the xpsm mutant strain, and vice versa. introducti ... | 2001 | 11133946 |
| ihfa gene of the bacterium myxococcus xanthus and its role in activation of carotenoid genes by blue light. | myxococcus xanthus responds to blue light by producing carotenoids. several regulatory genes are known that participate in the light action mechanism, which leads to the transcriptional activation of the carotenoid genes. we had already reported the isolation of a carotenoid-less, tn5-induced strain (mr508), whose mutant site was unlinked to the indicated regulatory genes. here, we show that omegamr508::tn5 affects all known light-inducible promoters in different ways. it blocks the activation o ... | 2001 | 11133949 |
| dsba and dsbc affect extracellular enzyme formation in pseudomonas aeruginosa. | dsba and dsbc proteins involved in the periplasmic formation of disulfide bonds in pseudomonas aeruginosa were identified and shown to play an important role for the formation of extracellular enzymes. mutants deficient in either dsba or dsbc or both genes were constructed, and extracellular elastase, alkaline phosphatase, and lipase activities were determined. the dsba mutant no longer produced these enzymes, whereas the lipase activity was doubled in the dsbc mutant. also, extracellar lipase p ... | 2001 | 11133952 |
| disulfide bond in pseudomonas aeruginosa lipase stabilizes the structure but is not required for interaction with its foldase. | pseudomonas aeruginosa secretes a 29-kda lipase which is dependent for folding on the presence of the lipase-specific foldase lif. the lipase contains two cysteine residues which form an intramolecular disulfide bond. variant lipases with either one or both cysteines replaced by serines showed severely reduced levels of extracellular lipase activity, indicating the importance of the disulfide bond for secretion of lipase through the outer membrane. wild-type and variant lipase genes fused to the ... | 2001 | 11133953 |
| hrpz(psph) from the plant pathogen pseudomonas syringae pv. phaseolicola binds to lipid bilayers and forms an ion-conducting pore in vitro. | the hrp gene clusters of plant pathogenic bacteria control pathogenicity on their host plants and ability to elicit the hypersensitive reaction in resistant plants. some hrp gene products constitute elements of the type iii secretion system, by which effector proteins are exported and delivered into plant cells. here, we show that the hrpz gene product from the bean halo-blight pathogen, pseudomonas syringae pv. phaseolicola (hrpz(psph)), is secreted in an hrp-dependent manner in p. syringae pv. ... | 2001 | 11134504 |
| hrpz(psph) from the plant pathogen pseudomonas syringae pv. phaseolicola binds to lipid bilayers and forms an ion-conducting pore in vitro. | the hrp gene clusters of plant pathogenic bacteria control pathogenicity on their host plants and ability to elicit the hypersensitive reaction in resistant plants. some hrp gene products constitute elements of the type iii secretion system, by which effector proteins are exported and delivered into plant cells. here, we show that the hrpz gene product from the bean halo-blight pathogen, pseudomonas syringae pv. phaseolicola (hrpz(psph)), is secreted in an hrp-dependent manner in p. syringae pv. ... | 2001 | 11134504 |
| analysis of the type iv fimbrial-subunit gene fima of xanthomonas hyacinthi: application in pcr-mediated detection of yellow disease in hyacinths. | a sensitive and specific detection method was developed for xanthomonas hyacinthi; this method was based on amplification of a subsequence of the type iv fimbrial-subunit gene fima from strain s148. the fima gene was amplified by pcr with degenerate dna primers designed by using the n-terminal and c-terminal amino acid sequences of trypsin fragments of fima. the nucleotide sequence of fima was determined and compared with the nucleotide sequences coding for the fimbrial subunits in other type iv ... | 2001 | 11157222 |
| molecular characterization of the iron-hydroxamate uptake system in staphylococcus aureus. | to investigate iron uptake, a chromosomal locus containing three consecutive open reading frames, designated fhuc, fhub, and fhud, was identified in staphylococcus aureus. whereas the fhuc gene encodes an atp-binding protein, fhub and fhud code for ferrichrome permeases and thus resemble an atp-binding cassette transporter. a fhub knockout mutant showed impaired uptake of iron bound to the siderophores but not of ferric chloride, suggesting that this operon is specific for siderophore-mediated i ... | 2001 | 11157278 |
| disulfide bond formation in secreton component pulk provides a possible explanation for the role of dsba in pullulanase secretion. | when expressed in escherichia coli, the 15 klebsiella oxytoca pul genes that encode the so-called pul secreton or type ii secretion machinery promote pullulanase secretion and the assembly of one of the secreton components, pulg, into pili. besides these pul genes, efficient pullulanase secretion also requires the host dsba gene, encoding a periplasmic disulfide oxidoreductase, independently of disulfide bond formation in pullulanase itself. two secreton components, the secretin pilot protein pu ... | 2001 | 11157944 |
| subset of hybrid eukaryotic proteins is exported by the type i secretion system of erwinia chrysanthemi. | erwinia chrysanthemi exports degradative enzymes by using a type i protein secretion system. the proteases secreted by this system lack an n-terminal signal peptide but contain a c-terminal secretion signal. to explore the substrate specificity of this system, we have expressed the e. chrysanthemi transporter system (prtdef genes) in escherichia coli and tested the ability of this abc transporter to export hybrid proteins carrying c-terminal fragments of e. chrysanthemi protease b. the c terminu ... | 2001 | 11157948 |
| cloning, sequences, and characterization of two chitinase genes from the antarctic arthrobacter sp. strain tad20: isolation and partial characterization of the enzymes. | arthrobacter sp. strain tad20, a chitinolytic gram-positive organism, was isolated from the sea bottom along the antarctic ice shell. arthrobacter sp. strain tad20 secretes two major chitinases, chia and chib (archia and archib), in response to chitin induction. a single chromosomal dna fragment containing the genes coding for both chitinases was cloned in escherichia coli. dna sequencing analysis of this fragment revealed two contiguous open reading frames coding for the precursors of archia (8 ... | 2001 | 11160110 |
| three-dimensional structure of erwinia chrysanthemi pectin methylesterase reveals a novel esterase active site. | most structures of neutral lipases and esterases have been found to adopt the common alpha/beta hydrolase fold and contain a catalytic ser-his-asp triad. some variation occurs in both the overall protein fold and in the location of the catalytic triad, and in some enzymes the role of the aspartate residue is replaced by a main-chain carbonyl oxygen atom. here, we report the crystal structure of pectin methylesterase that has neither the common alpha/beta hydrolase fold nor the common catalytic t ... | 2001 | 11162105 |
| from rags to riches: insights from the first genomic sequence of a plant pathogenic bacterium. | the recently published genomic sequence of xylella fastidiosa is the first for a free-living plant pathogen and provides clues to mechanisms of pathogenesis and survival in insect vectors. the sequence data should lead to improved control of this pathogen. | 2000 | 11178244 |
| role of the nucleoid-associated protein h-ns in the synthesis of virulence factors in the phytopathogenic bacterium erwinia chrysanthemi. | the ability of the enterobacterium erwinia chrysanthemi to induce pathogenesis in plant tissue is strongly related to the massive production of plant-cell-wall-degrading enzymes (pectinases, cellulases, and proteases). additional factors, including flagellar proteins and exopolysaccharides (eps), also are required for the efficient colonization of plants. production of these virulence factors, particularly pectate lyases, the main virulence determinant, is tightly regulated by environmental cond ... | 2001 | 11194867 |
| mexr repressor of the mexab-oprm multidrug efflux operon of pseudomonas aeruginosa: identification of mexr binding sites in the mexa-mexr intergenic region. | the mexr repressor of the mexab-oprm multidrug efflux operon of pseudomonas aeruginosa was purified as a c-terminal histidine-tagged protein by metal chelate affinity chromatography. the purified protein was shown to bind ca. 200 bp upstream of mexa, at two sites, each of which contains a repeat of the nucleotide sequence gttga in inverse orientation. dna sequence analysis identified mexa and mexr promoters within the mexr binding regions, consistent with the previously observed negative regulat ... | 2001 | 11208776 |
| effects exerted by transcriptional regulator pcau from acinetobacter sp. strain adp1. | protocatechuate degradation is accomplished in a multistep inducible catabolic pathway in acinetobacter sp. strain adp1. the induction is brought about by the transcriptional regulator pcau in concert with the inducer protocatechuate. pcau, a member of the new iclr family of transcriptional regulators, was shown to play a role in the activation of transcription at the promoter for the structural pca genes, leaving open the participation of additional activators. in this work we show that there i ... | 2001 | 11208784 |
| exchange of xcp (gsp) secretion machineries between pseudomonas aeruginosa and pseudomonas alcaligenes: species specificity unrelated to substrate recognition. | pseudomonas aeruginosa and pseudomonas alcaligenes are gram-negative bacteria that secrete proteins using the type ii or general secretory pathway, which requires at least 12 xcp gene products (xcpa and xcpp to -z). despite strong conservation of this secretion pathway, gram-negative bacteria usually cannot secrete exoproteins from other species. based on results obtained with erwinia, it has been proposed that the xcpp and/or xcpq homologs determine this secretion specificity (m. linderberg, g. ... | 2001 | 11208795 |
| effect of sequences of the active-site dipeptides of dsba and dsbc on in vivo folding of multidisulfide proteins in escherichia coli. | we have examined the role of the active-site cxxc central dipeptides of dsba and dsbc in disulfide bond formation and isomerization in the escherichia coli periplasm. dsba active-site mutants with a wide range of redox potentials were expressed either from the trc promoter on a multicopy plasmid or from the endogenous dsba promoter by integration of the respective alleles into the bacterial chromosome. the dsba alleles gave significant differences in the yield of active murine urokinase, a prote ... | 2001 | 11208797 |
| molecular characterization of global regulatory rna species that control pathogenicity factors in erwinia amylovora and erwinia herbicola pv. gypsophilae. | rsmb(ecc) specifies a nontranslatable rna regulator that controls exoprotein production and pathogenicity in soft rot-causing erwinia carotovora subsp. carotovora. this effect of rsmb(ecc) rna is mediated mostly by neutralizing the function of rsma(ecc), an rna-binding protein of e. carotovora subsp. carotovora, which acts as a global negative regulator. to determine the occurrence of functional homologs of rsmb(ecc) in non-soft-rot-causing erwinia species, we cloned the rsmb genes of e. amylovo ... | 2001 | 11222584 |
| functional characterization of a novel xylanase from a corn strain of erwinia chrysanthemi. | a beta-1,4-xylan hydrolase (xylanase a) produced by erwinia chrysanthemi d1 isolated from corn was analyzed with respect to its secondary structure and enzymatic function. the ph and temperature optima for the enzyme were found to be ph 6.0 and 35 degrees c, with a secondary structure under those conditions that consists of approximately 10 to 15% alpha-helices. the enzyme was still active at temperatures higher than 40 degrees c and at phs of up to 9.0. the loss of enzymatic activity at tempera ... | 2001 | 11222610 |
| mobilization function of the pbhr1 plasmid, a derivative of the broad-host-range plasmid pbbr1. | the pbhr1 plasmid is a derivative of the small (2.6-kb), mobilizable broad-host-range plasmid pbbr1, which was isolated from the gram-negative bacterium bordetella bronchiseptica (r. antoine and c. locht, mol. microbiol. 6:1785-1799, 1992). plasmid pbbr1 consists of two functional cassettes and presents sequence similarities with the transfer origins of several plasmids and mobilizable transposons from gram-positive bacteria. we show that the mob protein specifically recognizes a 52-bp sequence ... | 2001 | 11222611 |
| phase-variable expression of an operon encoding extracellular alkaline protease, a serine protease homolog, and lipase in pseudomonas brassicacearum. | the rhizobacterium pseudomonas brassicacearum forms phenotypic variants which do not show extracellular protease and lipase activity. the operon encoding these enzymes, a serine protease homolog, and a type i secretion machinery was characterized. transcriptional lacz gene fusions revealed that the expression of the operon is under the control of phase variation. | 2001 | 11222613 |
| structures of two highly homologous bacterial l-asparaginases: a case of enantiomorphic space groups. | quasi-enantiomorphic crystals of the y25f mutant of escherichia coli l-asparaginase and of the native erwinia chrysanthemi l-asparaginase were obtained in the hexagonal space groups p6(5)22 and p6(1)22, respectively. the structures of these highly homologous enzymes were solved by molecular replacement and were refined with data extending to 2.2-2.5 a. these structures were compared with each other, as well as with other l-asparaginase structures previously observed with different crystal packin ... | 2001 | 11223513 |
| effect of protracted high-dose l-asparaginase given as a second exposure in a berlin-frankfurt-münster-based treatment: results of the randomized 9102 intermediate-risk childhood acute lymphoblastic leukemia study--a report from the associazione italiana ematologia oncologia pediatrica. | to assess in a randomized study the therapeutic effect of the addition of high-dose l-asparaginase (hd asp) in the context of a berlin-frankfurt-münster (bfm)-based chemotherapy regimen for intermediate risk (ir) childhood acute lymphoblastic leukemia (all). | 2001 | 11230471 |
| soxr-dependent response to oxidative stress and virulence of erwinia chrysanthemi: the key role of sufc, an orphan abc atpase. | erwinia chrysanthemi causes soft-rot disease in a great variety of plants. in addition to the depolymerizing activity of plant cell wall-degrading enzymes, iron acquisition and resistance to oxidative stress contribute greatly to the virulence of this pathogen. here, we studied the pin10 locus originally thought to encode new virulence factors. the sequence analysis revealed six open reading frames that were homologous to the escherichia coli sufa, sufb, sufc, sufd, sufs and sufe genes. sequence ... | 2001 | 11251816 |
| type ii protein secretion is a subset of the pild-dependent processes that facilitate intracellular infection by legionella pneumophila. | previously, we had demonstrated that a legionella pneumophila prepilin peptidase (pild) mutant does not produce type iv pili and shows reduced secretion of enzymatic activities. moreover, it displays a distinct colony morphology and a dramatic reduction in intracellular growth within amoebae and macrophages, two phenotypes that are not exhibited by a pilin (pile(l)) mutant. to determine whether these pild-dependent defects were linked to type ii secretion, we have constructed two new mutants of ... | 2001 | 11254562 |
| identification of the exported proteins of the oral opportunistic pathogen actinobacillus actinomycetemcomitans by using alkaline phosphatase fusions. | a phoa fusion library of actinobacillus actinomycetemcomitans genomic dna has been screened to identify genes encoding exported and secreted proteins. a total of 8,000 colonies were screened, and 80 positive colonies were detected. from these, 48 genes were identified with (i) more than half having homology to known or hypothetical haemophilus influenzae genes, (ii) 14 having no ascribed function, and (iii) 4 having very limited or no homology to known genes. the proteins encoded by these genes ... | 2001 | 11254647 |
| pectate lyase a, an enzymatic subunit of the clostridium cellulovorans cellulosome. | clostridium cellulovorans uses not only cellulose but also xylan, mannan, pectin, and several other carbon sources for its growth and produces an extracellular multienzyme complex called the cellulosome, which is involved in plant cell wall degradation. here we report a gene for a cellulosomal subunit, pectate lyase a (pela), lying downstream of the engy gene, which codes for cellulosomal enzyme engy. pela is composed of an orf of 2,742 bp and encodes a protein of 914 aa with a molecular weight ... | 2001 | 11259664 |
| an inner membrane platform in the type ii secretion machinery of gram-negative bacteria. | the type ii secretion machinery allows most gram-negative bacteria to deliver virulence factors into their surroundings. we report that in erwinia chrysanthemi, gspe (the putative ntpase), gspf, gspl and gspm constitute a complex in the inner membrane that is presumably used as a platform for assembling other parts of the secretion machinery. the gspe-gspf-gspl-gspm complex was demonstrated by two methods: (i) co-immunoprecipitation of gspe-gspf-gspl with antibodies raised against either gspe or ... | 2001 | 11266368 |
| chunnel vision. export and efflux through bacterial channel-tunnels. | the escherichia coli tolc protein is central to toxin export and drug efflux across the inner and outer cell membranes and the intervening periplasmic space. the crystal structure has revealed that tolc assembles into a remarkable alpha-helical trans-periplasmic cylinder (tunnel) embedded in the outer membrane by a contiguous beta-barrel (channel), so providing a large duct open to the outside environment. the channel-tunnel structure is conserved in tolc homologues throughout gram-negative bact ... | 2000 | 11269495 |
| relative effects on virulence of mutations in the sap, pel, and hrp loci of erwinia chrysanthemi. | we constructed strains of erwinia chrysanthemi ec16 with multiple mutations involving three virulence systems in this bacterium, namely pel (coding for the major pectate lyases pelabce), hrp (hypersensitive response and pathogenicity), and sap (sensitivity to antimicrobial peptides). the relative effects on virulence of those mutations have been analyzed on potato tubers and chicory leaves. in potato tubers, the sap mutation (bt105) had a greater effect in the reduction of the virulence than the ... | 2001 | 11277436 |
| pyruvated galactose and oligosaccharides from erwinia chrysanthemi ech6 extracellular polysaccharide. | the acidic extracellular polysaccharide of ech6 was depolymerized by fuming hcl. the pyruvated sugars were isolated and characterized by methods that included a combination of low-pressure gel-filtration and high-ph anion-exchange chromatographies, methylation linkage analyses, mass (gc-ms and maldi-tof ms) and 1h nmr (1d and 2d) spectroscopies. the following pyruvated sugars were obtained: 4,6-o-(1-carboxyethylidene)-d-galp; 4,6-o-(1-carboxyethylidene)- alpha-d-galp-(1-->4)-beta-d-glcap-(1-->3) ... | 2001 | 11284505 |
| expression of bar in the plastid genome confers herbicide resistance. | phosphinothricin (ppt) is the active component of a family of environmentally safe, nonselective herbicides. resistance to ppt in transgenic crops has been reported by nuclear expression of a bar transgene encoding phosphinothricin acetyltransferase, a detoxifying enzyme. we report here expression of a bacterial bar gene (b-bar1) in tobacco (nicotiana tabacum cv petit havana) plastids that confers field-level tolerance to liberty, an herbicide containing ppt. we also describe a second bacterial ... | 2001 | 11299340 |
| cloning of two pectate lyase genes from the marine antarctic bacterium pseudoalteromonas haloplanktis strain ant/505 and characterization of the enzymes. | a marine antarctic psychrotolerant bacterium (strain ant/505), isolated from sea ice-covered surface water from the southern ocean, showed pectinolytic activity on citrus pectin agar. the sequencing of the 16s rrna of isolate ant/505 indicates a taxonomic affiliation to pseudoalteromonas haloplanktis. the supernatant of this strain showed three different pectinolytic activities after growth on citrus pectin. by activity screening of a genomic dna library of isolate ant/505 in escherichia coli, t ... | 2001 | 11302501 |
| the cela gene, encoding a glycosyl hydrolase family 3 beta-glucosidase in azospirillum irakense, is required for optimal growth on cellobiosides. | the cela beta-glucosidase of azospirillum irakense, belonging to glycosyl hydrolase family 3 (ghf3), preferentially hydrolyzes cellobiose and releases glucose units from the c(3), c(4), and c(5) oligosaccharides. the growth of a deltacela mutant on these cellobiosides was affected. in a. irakense, the ghf3 beta-glucosidases appear to be functional alternatives for the ghf1 beta-glucosidases in the assimilation of beta-glucosides by other bacteria. | 2001 | 11319128 |
| the pecm protein of the phytopathogenic bacterium erwinia chrysanthemi, membrane topology and possible involvement in the efflux of the blue pigment indigoidine. | the pecs regulatory locus negatively modulates the expression of many virulence genes in erwinia chrysanthemi. this locus consists of two genes, pecs and pecm, divergently transcribed. previous studies have shown that pecs down-regulates the expression of both pecsand pecmgenes and that pecm is required for full pecs activity. computer-aided hydropathy analysis of pecm predicted the presence of between 8 to 10 potential transmembrane segments. we analyzed the membrane topology of pecm using the ... | 2001 | 11321588 |
| osmoregulated periplasmic glucans of erwinia chrysanthemi. | we report the initial characterization of the osmoregulated periplasmic glucans (opgs) of erwinia chrysanthemi. opgs are intrinsic components of the bacterial envelope necessary to the pathogenicity of this phytopathogenic enterobacterium (f. page, s. altabe, n. hugouvieux-cotte-pattat, j.-m. lacroix, j. robert-baudouy and j.-p. bohin, j. bacteriol. 183:0000-0000, 2001 [companion in this issue]). opgs were isolated by trichloracetic acid treatment and gel permeation chromatography. the synthesis ... | 2001 | 11325941 |
| osmoregulated periplasmic glucan synthesis is required for erwinia chrysanthemi pathogenicity. | erwinia chrysanthemi is a phytopathogenic enterobacterium causing soft rot disease in a wide range of plants. osmoregulated periplasmic glucans (opgs) are intrinsic components of the gram-negative bacterial envelope. we cloned the opggh operon of e. chrysanthemi, encoding proteins involved in the glucose backbone synthesis of opgs, by complementation of the homologous locus mdogh of escherichia coli. opgg and opgh show a high level of similarity with mdog and mdoh, respectively, and mutations in ... | 2001 | 11325942 |
| the pdz domain of outc and the n-terminal region of outd determine the secretion specificity of the type ii out pathway of erwinia chrysanthemi. | the plant pathogens erwinia chrysanthemi and erwinia carotovora secrete multiple exoproteins by a type ii pathway, the out system. secretion in erwinia is species-specific: exoproteins of one species cannot be secreted by the other. we analysed the role of two components of the out system, the bitopic inner membrane protein outc and the secretin outd, in the specific recognition of secreted proteins. we demonstrated that the pdz domain of outc determines its secretion specificity towards certain ... | 2001 | 11327762 |
| structural basis for the activity and substrate specificity of erwinia chrysanthemi l-asparaginase. | bacterial l-asparaginases, enzymes that catalyze the hydrolysis of l-asparagine to aspartic acid, have been used for over 30 years as therapeutic agents in the treatment of acute childhood lymphoblastic leukemia. other substrates of asparaginases include l-glutamine, d-asparagine, and succinic acid monoamide. in this report, we present high-resolution crystal structures of the complexes of erwinia chrysanthemi l-asparaginase (era) with the products of such reactions that also can serve as substr ... | 2001 | 11341830 |
| combined, functional genomic-biochemical approach to intermediary metabolism: interaction of acivicin, a glutamine amidotransferase inhibitor, with escherichia coli k-12. | acivicin, a modified amino acid natural product, is a glutamine analog. thus, it might interfere with metabolism by hindering glutamine transport, formation, or usage in processes such as transamidation and translation. this molecule prevented the growth of escherichia coli in minimal medium unless the medium was supplemented with a purine or histidine, suggesting that the hishf enzyme, a glutamine amidotransferase, was the target of acivicin action. this enzyme, purified from e. coli, was inhib ... | 2001 | 11344143 |
| type ii secretion and pathogenesis. | 2001 | 11349009 | |
| biochemical and x-ray crystallographic studies on shikimate kinase: the important structural role of the p-loop lysine. | shikimate kinase, despite low sequence identity, has been shown to be structurally a member of the nucleoside monophosphate (nmp) kinase family, which includes adenylate kinase. in this paper we have explored the roles of residues in the p-loop of shikimate kinase, which forms the binding site for nucleotides and is one of the most conserved structural features in proteins. in common with many members of the p-loop family, shikimate kinase contains a cysteine residue 2 amino acids upstream of th ... | 2001 | 11369852 |
| beta-elimination of glucosyluronic residues during methylation of an acidic polysaccharide from erwinia chrysanthemi cu 643. | the erwinia chrysanthemi cu643 eps has a linear hexasaccharide repeating unit in which a 4-linked uronic acid residue is present. the eps was methylated by either the naoh-me2so-mei or li-dimsyl procedure. maldi-tof ms analysis of the methylated products indicates that the beta-eliminative degradation occurs during the methylation, as characterized by serial fragments of the hexasaccharide repeating units. the degradation was clearly defined from the methylation of a glucosyluronic-containing py ... | 2001 | 11376611 |
| essential role of superoxide dismutase on the pathogenicity of erwinia chrysanthemi strain 3937. | the soda gene from erwinia chrysanthemi strain 3937 was cloned by functional complementation of an escherichia coli soda sodb mutant and sequenced. we identified a 639-bp open reading frame, which encodes a protein that is 85% identical to the e. coli manganese-containing superoxide dismutase mnsod. promoter elements of this gene were identified by transcriptional mapping experiments. we constructed an e. chrysanthemi deltasoda mutant by reverse genetics. the deltasoda mutation resulted in the a ... | 2001 | 11386371 |
| control of exut activity for galacturonate transport by the negative regulator exur in erwinia chrysanthemi ec16. | the negative regulatory protein exur in erwinia chrysanthemi regulates expression of the galacturonate uptake (exut) and utilization (uxaa, uxab, uxac) genes. we cloned and determined the nucleotide sequence of the exur gene from e. chrysanthemi ec16. analysis of the deduced amino acid sequence indicates that this protein possesses a helix-turn-helix motif and belongs to the gntr family of transcriptional repressors. northern blot analysis and studies with transcriptional fusions of exut in wild ... | 2001 | 11386378 |
| resolution of four pectate lyase structural genes of erwinia chrysanthemi (ec16) and characterization of the enzymes produced in escherichia coli. | 1987 | 11394411 | |
| analysis of the pilq secretin from neisseria meningitidis by transmission electron microscopy reveals a dodecameric quaternary structure. | pilq is a member of the secretin family of outer membrane proteins and is specifically involved in secretion of type iv pili in neisseria meningitidis, neisseria gonorrhoeae, and pseudomonas aeruginosa. the quaternary structure of pilq from n. meningitidis was analyzed by transmission electron microscopy by using a negative stain. single particle averaging was carried out with a total data set of 650 individual particles, which produced a projection map generated from 296 particles at an estimat ... | 2001 | 11395444 |
| diversity of polyamine patterns in soft rot pathogens and other plant-associated members of the enterobacteriaceae. | polyamine profiles of 91 pectolytic and other plant-associated strains from 30 taxa of the enterobacteriaceae were obtained by gradient high performance liquid chromatography (hplc). pectobacterium carotovorum, basonym erwinia carotovora, contained a high amount of putrescine and less diaminopropane. diaminopropane was absent in pectobacterium chrysanthemi, basonym e. chrysanthemi, whereas cadaverine was present in addition to the major compound putrescine. this chemotaxonomic difference reflect ... | 2001 | 11403399 |
| identification of proteus mirabilis mutants with increased sensitivity to antimicrobial peptides. | antimicrobial peptides (aps) are important components of the innate defenses of animals, plants, and microorganisms. however, some bacterial pathogens are resistant to the action of aps. for example, proteus mirabilis is highly resistant to the action of aps, such as polymyxin b (pm), protegrin, and the synthetic protegrin analog ib-367. to better understand this resistance, a transposon mutagenesis approach was used to generate p. mirabilis mutants sensitive to aps. four unique pm-sensitive mut ... | 2001 | 11408219 |
| backbone h(n), n, calpha, c' and cbeta assignment of the 25 kda peptide methionine sulfoxide reductase from erwinia chrysanthemi. | 2001 | 11430764 | |
| listeria pathogenesis and molecular virulence determinants. | the gram-positive bacterium listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. pregnant women, neonates, the elderly, and debilitated or immunocompromised patients in general are predominantly affected, although the disease can also develop in normal individuals. clinical manifestations of invasive listeriosis are usually severe and include abortion, sepsis, and meningoencephalitis. listeriosis can also manifest as a febrile gastroente ... | 2001 | 11432815 |
| complex regulation of the organic hydroperoxide resistance gene (ohr) from xanthomonas involves ohrr, a novel organic peroxide-inducible negative regulator, and posttranscriptional modifications. | analysis of the sequence immediate upstream of ohr revealed an open reading frame, designated ohrr, with the potential to encode a 17-kda peptide with moderate amino acid sequence homology to the marr family of negative regulators of gene expression. ohrr was transcribed as bicistronic mrna with ohr, while ohr mrna was found to be 95% monocistronic and 5% bicistronic with ohrr. expression of both genes was induced by tert-butyl hydroperoxide (tbooh) treatment. high-level expression of ohrr negat ... | 2001 | 11443074 |
| novel topology of bfpe, a cytoplasmic membrane protein required for type iv fimbrial biogenesis in enteropathogenic escherichia coli. | enteropathogenic escherichia coli (epec) produces the bundle-forming pilus (bfp), a type iv fimbria that has been implicated in virulence, autoaggregation, and localized adherence to epithelial cells. the bfpe gene is one of a cluster of bfp genes previously shown to encode functions that direct bfp biosynthesis. here, we show that an epec strain carrying a nonpolar mutation in bfpe fails to autoaggregate, adhere to hep-2 cells, or form bfp, thereby demonstrating that bfpe is required for bfp bi ... | 2001 | 11443077 |
| the type iv fimbrial subunit gene (fima) of dichelobacter nodosus is essential for virulence, protease secretion, and natural competence. | dichelobacter nodosus is the essential causative agent of footrot in sheep. the major d. nodosus-encoded virulence factors that have been implicated in the disease are type iv fimbriae and extracellular proteases. to examine the role of the fimbriae in virulence, allelic exchange was used to insertionally inactivate the fima gene, which encodes the fimbrial subunit protein, from the virulent type g d. nodosus strain vcs1703a. detailed analysis of two independently derived fima mutants revealed t ... | 2001 | 11443078 |
| dna microarray-mediated transcriptional profiling of the escherichia coli response to hydrogen peroxide. | the genome-wide transcription profile of escherichia coli cells treated with hydrogen peroxide was examined with a dna microarray composed of 4,169 e. coli open reading frames. by measuring gene expression in isogenic wild-type and oxyr deletion strains, we confirmed that the peroxide response regulator oxyr activates most of the highly hydrogen peroxide-inducible genes. the dna microarray measurements allowed the identification of several new oxyr-activated genes, including the hemh heme biosyn ... | 2001 | 11443091 |
| extracellular polysaccharides of modified strains of erwinia spp. | the structure of the extracellular polysaccharide (eps) produced by erwinia chrysanthemi strain a2148 has been determined using low pressure size-exclusion and anion-exchange chromatographies, high ph anion-exchange chromatography, glycosyl-linkage analysis, and 1d 1h nmr spectroscopy. the polysaccharide is structurally similar, if not identical, to the eps produced by e. chrysanthemi strain a350. a streptomycin-resistant strain of e. chrysanthemi ech6 (ech6s(+)) has been generated and has an el ... | 2001 | 11454336 |
| structure-function analysis of bfpb, a secretin-like protein encoded by the bundle-forming-pilus operon of enteropathogenic escherichia coli. | production of type iv bundle-forming pili by enteropathogenic escherichia coli (epec) requires bfpb, an outer-membrane lipoprotein and member of the secretin protein superfamily. bfpb was found to compose a ring-shaped, high-molecular-weight outer-membrane complex that is stable in 4% sodium dodecyl sulfate at temperatures of < or = 65 degrees c. chemical cross-linking and immunoprecipitation experiments disclosed that the bfpb multimeric complex interacts with bfpg, and mutational studies showe ... | 2001 | 11466288 |
| identification and functional characterization of cbar, a marr-like modulator of the cbaabc-encoded chlorobenzoate catabolism pathway. | in comamonas testosteroni br60 (formerly alcaligenes sp. strain br60), catabolism of the pollutant 3-chlorobenzoate (3cba) is initiated by enzymes encoded by cbaabc, an operon found on composite transposon tn5271 of plasmid pbrc60. the cbaabc gene product cbaabc converts 3cba to protocatechuate (pca) and 5-cl-pca, which are then metabolized by the chromosomal pca meta (extradiol) ring fission pathway. in this study, cbaa was found to possess a sigma(70) type promoter. o(2) uptake experiments wit ... | 2001 | 11472929 |
| gene cluster for assembly of pilus colonization factor antigen iii of enterotoxigenic escherichia coli. | the assembly of pilus colonization factor antigen iii (cfa/iii) of enterotoxigenic escherichia coli (etec) requires the processing of cfa/iii major pilin (cofa) by a prepilin peptidase (cofp), similar to other type iv pilus formation systems. cofa is produced initially as a 26.5-kda preform pilin (prepilin) and then processed to a 20.5-kda mature pilin by cofp which is predicted to be localized in the inner membrane. in the present experiment, we determined the nucleotide sequence of the whole r ... | 2001 | 11500465 |
| type ii protein secretion in gram-negative pathogenic bacteria: the study of the structure/secretion relationships of the cellulase cel5 (formerly egz) from erwinia chrysanthemi. | erwinia chrysanthemi, a gram-negative plant pathogen, secretes the cellulase cel5 (formerly egz) via the type ii secretion pathway (referred to as out). cel5 is composed of two domains, a large n-terminal catalytic domain (390 amino acid residues) and a small c-terminal cellulose-binding domain (62 amino acid residues) separated by a linker region. a combination of mutagenesis and structural analysis permitted us to investigate the structure/secretion relationships with respect to the catalytic ... | 2001 | 11501995 |
| the relationship between the l1 and l2 domains of the insulin and epidermal growth factor receptors and leucine-rich repeat modules. | leucine-rich repeats are one of the more common modules found in proteins. the leucine-rich repeat consensus motif is lxxlxlxxnxlxxlxxlxxlxx- where the first 11-12 residues are highly conserved and the remainder of the repeat can vary in size leucine-rich repeat proteins have been subdivided into seven subfamilies, none of which include members of the epidermal growth factor receptor or insulin receptor families despite the similarity between the 3d structure of the l domains of the type i insul ... | 2001 | 11504559 |
| low-temperature lipase from psychrotrophic pseudomonas sp. strain kb700a. | we have previously reported that a psychrotrophic bacterium, pseudomonas sp. strain kb700a, which displays sigmoidal growth even at -5 degrees c, produced a lipase. a genomic dna library of strain kb700a was introduced into escherichia coli tg1, and screening on tributyrin-containing agar plates led to the isolation of the lipase gene. sequence analysis revealed an open reading frame (kb-lip) consisting of 1,422 nucleotides that encoded a protein (kb-lip) of 474 amino acids with a molecular mass ... | 2001 | 11526006 |
| enhancer-binding proteins hrpr and hrps interact to regulate hrp-encoded type iii protein secretion in pseudomonas syringae strains. | in pseudomonas syringae strains, the hrp-hrc pathogenicity island consists of an hrpl-dependent regulon that encodes a type iii protein translocation complex and translocated effector proteins required for pathogenesis. hrpr and hrps function as positive regulatory factors for the hrpl promoter, but their mechanism of action has not been established. both hrpr and hrps are structurally related to enhancer-binding proteins, but they lack receiver domains and do not appear to require a cognate pro ... | 2001 | 11544221 |
| peptide methionine sulfoxide reductase (msra) is a virulence determinant in mycoplasma genitalium. | mycoplasma genitalium is the smallest self-replicating microorganism and is implicated in human diseases, including urogenital and respiratory infections and arthritides. m. genitalium colonizes host cells primarily through adherence mechanisms mediated by a network of surface-associated membrane proteins, including adhesins and cytadherence-related proteins. in this paper, we show that cytadherence in m. genitalium is affected by an unrelated protein known as peptide methionine sulfoxide reduct ... | 2001 | 11544227 |
| cloning and characterization of an intracellular isoamylase gene from pectobacterium chrysanthemi py35. | the gene encoding an intracellular isoamylase from the pectobacterium chrysanthemi py35 was cloned in escherichia coli dh5alpha and sequenced. the isoamylase gene (amyx) had an open reading frame of 1974 bp encoding 657 amino acid residues with a calculated molecular weight of 74,151 da. the molecular weight of the enzyme was also estimated to be 74 kda by activity staining of a sds-pa gel. isoamylase from p. chrysanthemi py35 had 59% pairwise amino acid identity with glycogen debranching enzyme ... | 2001 | 11554733 |
| identification of togmnab, an abc transporter which mediates the uptake of pectic oligomers in erwinia chrysanthemi 3937. | the bacterium erwinia chrysanthemi, which causes soft rot disease on various plants, is able to use pectin as a carbon source for growth. knowledge of the critical step in pectin catabolism which allows the entry of pectic oligomers into the cells is scarce. we report here the first example of a transport system involved in the uptake of pectic oligomers. the togmnab transporter of e. chrysanthemi is a member of the atp-binding cassette (abc) superfamily. togm and togn are homologous to the inne ... | 2001 | 11555291 |
| two transporters, togt and togmnab, are responsible for oligogalacturonide uptake in erwinia chrysanthemi 3937. | erwinia chrysanthemi causes soft rot of plants by secreting pectinases which cleave pectin, a polysaccharide cementing the plant cell wall constituents. we demonstrated that two transporters mediate the uptake of the extracellularly formed oligomers in e. chrysanthemi. togmnab, a multicomponent transporter member of the atp-binding cassette (abc) superfamily, is only partially responsible for the uptake of pectic oligomers. its action is completed by that of the second transporter, togt, a membe ... | 2001 | 11555292 |
| nonspecific adherence and fibril biogenesis by actinobacillus actinomycetemcomitans: tada protein is an atpase. | cells of actinobacillus actinomycetemcomitans, a gram-negative pathogen responsible for an aggressive form of juvenile periodontitis, form tenaciously adherent biofilms on solid surfaces. the bacteria produce long fibrils of bundled pili, which are required for adherence. mutations in flp-1, which encodes the major subunit of the pili, or any of seven downstream tad genes (tadabcdefg) cause defects in fibril production, autoaggregation, and tenacious adherence. we proposed that the tad genes spe ... | 2001 | 11566992 |
| a partially folded intermediate conformation is induced in pectate lyase c by the addition of 8-anilino-1-naphthalenesulfonate (ans). | addition of 8-anilino-1-naphthalenesulfonate (ans) to acid-denatured pectate lyase c (pelc) leads to a large increase in the fluorescence quantum yield near 480 nm. the conventional interpretation of such an observation is that the ans is binding to a partially folded intermediate such as a molten globule. far-ultraviolet circular dichroism demonstrates that the enhanced fluorescence results from the induction of a partially folded protein species that adopts a large fraction of native-like seco ... | 2001 | 11567103 |
| genetic organization of the pantoea stewartii subsp. stewartii hrp gene cluster and sequence analysis of the hrpa, hrpc, hrpn, and wtse operons. | the hrp/wts gene cluster of pantoea stewartii subsp. stewartii is required for pathogenicity on sweet corn and the ability to elicit a hypersensitive response (hr) in tobacco. site-directed transposon mutagenesis and nucleotide sequencing were used to identify hrp/wts genes within the left 20 kb of this cluster. seventeen open reading frames (orfs) comprise seven genetic complementation groups. these orfs share homology with hrp and dsp genes from erwinia amylovora, erwinia chrysanthemi, and pse ... | 2001 | 11605961 |
| monitoring of erwinia asparaginase therapy in childhood all in the nordic countries. | evaluation of l-asparaginase therapy in the nopho-92 all-protocol (treatment protocol of acute lymphoblastic leukaemia of the nordic society of paediatric haematology and oncology, initiated in 1992) after intravenous and intramuscular administration of erwinia asparaginase during induction and re-induction therapy. | 2001 | 11678787 |
| glycine betaine loses its osmoprotective activity in a bspa strain of erwinia chrysanthemi. | erwinia chrysanthemi insertion mutants were isolated that grew poorly specifically in the presence of glycine betaine (gb) or its analogues in high-salt media. transposon insertions were found to affect the bspa gene, which forms an operon including the psd locus coding for phosphatidylserine decarboxylase. initial gb uptake is not affected by the bspa mutation. however, in high-salt medium, its initial accumulation is followed by a reduced glucose uptake and a release of gb but not a loss of vi ... | 2001 | 11679069 |
| input of protein to lake water microcosms affects expression of proteolytic enzymes and the dynamics of pseudomonas spp. | the objective of this study was to determine how an input of protein to lake water affects expression of a proteolytic potential and influences the abundance and composition of a specific group of bacteria. pseudomonas spp. were chosen as a target group that can be recovered on selective growth media and contain both proteolytic and nonproteolytic strains. amendment with 2 mg of casein per liter increased total proteinase activity (hydrolysis of [(3)h]casein) by 74%, leucine-aminopeptidase activ ... | 2001 | 11679313 |
| identification and characterization of the three chitin-binding domains within the multidomain chitinase chi92 from aeromonas hydrophila jp101. | the gene (chi92) encoding the extracellular chitinase of aeromonas hydrophila jp101 has been cloned and expressed in escherichia coli. the mature form of chi92 is an 842-amino-acid (89.830-kda) modular enzyme comprised of a family 18 catalytic domain, an unknown-function region (the a region), and three chitin-binding domains (chbds; chi92-n, chbd(ci), and chbd(cii)). the c-terminally repeated chbds, chbd(ci) and chbd(cii), were grouped into family v of cellulose-binding domains on the basis of ... | 2001 | 11679332 |
| comparative evaluation of pectolytic and proteolytic enzyme production by free and immobilized cells of some strains of the phytopathogenic erwinia chrysanthemi. | whole cells of the phytopathogenic erwinia chrysanthemi strains were immobilized in k-carrageenan and grown in high-calcium xanthomonas campestris medium containing sodium polypectate as carbon source. all the strains used survived immobilization into k-carrageenan beads. immobilized e. chrysanthemi strains displayed higher pectolytic and proteolytic enzyme activities than free cells in liquid suspension. carrageenan immobilization techniques could provide a system to mimic the conditions of e. ... | 2001 | 11687933 |
| chrysobactin-dependent iron acquisition in erwinia chrysanthemi. functional study of a homolog of the escherichia coli ferric enterobactin esterase. | under iron limitation, the plant pathogen erwinia chrysanthemi produces the catechol-type siderophore chrysobactin, which acts as a virulence factor. it can also use enterobactin as a xenosiderophore. we began this work by sequencing the 5'-upstream region of the fct-cbsceba operon, which encodes the ferric chrysobactin receptor and proteins involved in synthesis of the catechol moiety. we identified a new iron-regulated gene (cbsh) transcribed divergently relative to the fct gene, the translate ... | 2002 | 11694506 |
| isolation and characterization of escherichia coli tolc mutants defective in secreting enzymatically active alpha-hemolysin. | this study describes the isolation and characterization of a unique class of tolc mutants that, under steady-state growth conditions, secreted normal levels of largely inactive alpha-hemolysin. unlike the reduced activity in the culture supernatants, the cell-associated hemolytic activity in these mutants was identical to that in the parental strain, thus reflecting a normal intracellular toxin activation event. treatment of the secreted toxin with guanidine hydrochloride significantly restored ... | 2001 | 11698380 |
| the n terminus of the hasa protein and the secb chaperone cooperate in the efficient targeting and secretion of hasa via the atp-binding cassette transporter. | secretion of the hasa hemophore is mediated by a c-terminal secretion signal as part of an atp-binding cassette (abc) pathway in the gram-negative bacterium serratia marcescens. we reconstituted the hasa secretion pathway in escherichia coli. in e. coli, this pathway required three specific secretion functions and secb, the general chaperone of the sec pathway that recognizes hasa. the secretion of the isolated c-terminal secretion signal was not secb-dependent. we have previously shown that int ... | 2002 | 11698405 |
| withholding and exchanging iron: interactions between erwinia spp. and their plant hosts. | the critical role of iron in plant host-parasite relationships has been elucidated in diseases as different as the soft rot and fire blight incited by erwinia chrysanthemi and e. amylovora, respectively. as in animal infections, the role of iron and its ligands in the virulence of plant pathogens seems to be more subtle than might be expected, and is intimately related to the life cycle of the pathogen within its host. this review discusses how iron, because of its unique position in biological ... | 1999 | 11701826 |
| roles of dna adenine methylation in regulating bacterial gene expression and virulence. | 2001 | 11705888 | |
| mxim and mxij, base elements of the mxi-spa type iii secretion system of shigella, interact with and stabilize the mxid secretin in the cell envelope. | the type iii secretion pathway is broadly distributed across many parasitic bacterial genera and serves as a mechanism for delivering effector proteins to eukaryotic cell surface and cytosolic targets. while the effectors, as well as the host responses elicited, differ among type iii systems, they all utilize a conserved set of 9 to 11 proteins that together form a bacterial envelope-associated secretory organelle or needle complex. the general structure of the needle complex consists of a trans ... | 2001 | 11717255 |
| characterization of pseudomonas aeruginosa chitinase, a gradually secreted protein. | the gram-negative bacterium pseudomonas aeruginosa secretes many proteins into its extracellular environment via the type i, ii, and iii secretion systems. in this study, a gene, chic, coding for an extracellular chitinolytic enzyme, was identified. the chic gene encodes a polypeptide of 483 amino acid residues, without a typical n-terminal signal sequence. nevertheless, an n-terminal segment of 11 residues was found to be cleaved off in the secreted protein. the protein shows sequence similarit ... | 2001 | 11717261 |
| complex regulatory network controls initial adhesion and biofilm formation in escherichia coli via regulation of the csgd gene. | the escherichia coli ompr/envz two-component regulatory system, which senses environmental osmolarity, also regulates biofilm formation. up mutations in the ompr gene, such as the ompr234 mutation, stimulate laboratory strains of e. coli to grow as a biofilm community rather than in a planktonic state. in this report, we show that the ompr234 protein promotes biofilm formation by binding the csgd promoter region and stimulating its transcription. the csgd gene encodes the transcription regulator ... | 2001 | 11717281 |
| crystallization and preliminary x-ray diffraction analysis of shikimate kinase from mycobacterium tuberculosis in complex with mgadp. | shikimate kinase (sk) from mycobacterium tuberculosis (mt) was overexpressed in escherichia coli, purified and cocrystallized with mgadp in hanging drops using the vapor-diffusion procedure with peg 4000 and 2-propanol as precipitants at ph 7.5. the crystal of mtsk-mgadp, which diffracted to 2.2 a resolution, belonged to space group p3(2)21 or p3(1)21, with unit-cell parameters a = b = 64.01, c = 92.41 a. there was one mtsk molecule in the asymmetric unit. molecular-replacement trials with the c ... | 2001 | 11717501 |
| the conserved methionine residue of the metzincins: a site-directed mutagenesis study. | the metalloprotease clan of the metzincins derive their name from the presence of a conserved methionine residue that is located on the c-terminal side of the zinc-binding consensus sequence hexxhxxgxxh. this methionine residue is located in a rather divergent part of the primary sequence but is structurally very well conserved. it is located under the pyramidal base of the three histidine residues that coordinate the catalytic zinc ion and is not involved in any direct contact with the metal no ... | 2001 | 11718552 |
| protease c of erwinia chrysanthemi: the crystal structure and role of amino acids y228 and e189. | prtc, a metallo-protease secreted by erwinia chrysanthemi, is a member of the serralysin family and hence belongs to the metzincin superfamily. while the crystal structures of representatives of all metzincin subfamilies have been elucidated in the past, there is still some controversy about the reaction mechanism and the role of certain characteristic amino acids in the active centre. in this study, we probed the role of tyr228 and glu189 by site-directed mutagenesis and x-ray crystallography. ... | 2001 | 11718553 |
| structure of human dipeptidyl peptidase i (cathepsin c): exclusion domain added to an endopeptidase framework creates the machine for activation of granular serine proteases. | dipeptidyl peptidase i (dppi) or cathepsin c is the physiological activator of groups of serine proteases from immune and inflammatory cells vital for defense of an organism. the structure presented shows how an additional domain transforms the framework of a papain-like endopeptidase into a robust oligomeric protease-processing enzyme. the tetrahedral arrangement of the active sites exposed to solvent allows approach of proteins in their native state; the massive body of the exclusion domain fa ... | 2001 | 11726493 |
| molecular cloning and sequencing of the gene encoding an exopolygalacturonase of a bacillus isolate and properties of its recombinant enzyme. | an exopolygalacturonase (exo-pgase; ec 3.2.1.82) was found in the culture broth of a bacillus isolate. the gene encoding the exo-pgase, pehk, was cloned by polymerase chain reaction using mixed primers designed from n-terminal and internal amino acid (aa) sequences of the enzyme (pehk). the determined nucleotide (nt) sequence of pehk revealed a 2940 bp open reading frame (980 aa) that encoded a putative signal sequence (27 aa) and a mature protein (953 aa; 103810 da). the recombinant enzyme was ... | 2001 | 11750764 |