Publications

c-terminal secretion signal of an erwinia chrysanthemi protease secreted by a signal peptide-independent pathway: proton nmr and cd conformational studies in membrane-mimetic environments.	the detailed structure of a 68-residue chimeric peptide encompassing the 56 last c-terminal residues of erwinia chrysanthemi protease g has been investigated by using circular dichroism and nmr spectroscopies. the peptide which contains the secretion signal of prtg was solubilized either in aqueous solvent, in trifluoroethanol (tfe)/h2o mixtures, or in dodecyl beta-d-maltoside detergent. the peptide helical content increases upon tfe and detergent additions. a stable conformation is reached at 4 ...	1994	8204613
isolation and characterization of a second exe operon required for extracellular protein secretion in aeromonas hydrophila.	strain c5.84 is a tn5-751 insertion mutant of aeromonas hydrophila which is unable to secrete extracellular proteins, instead accumulating them in the periplasm (b. jiang and s.p. howard, j. bacteriol. 173:1241-1249, 1991). a 3.5-kb bglii fragment which complements this mutation was isolated from the chromosome of the parent strain. analysis of this fragment revealed an operon-like structure with two complete genes, exea and exeb, a functional promoter 5' to the exea gene, and a 13-bp inverted r ...	1994	7961440
molecular analysis of the erwinia chrysanthemi region containing the kdga and zwf genes.	the pathways of pectin and galacturonate catabolism in erwinia chrysanthemi converge to form a common intermediate, 2-keto-3-deoxygluconate, which is phosphorylated to form 2-keto-3-deoxy-6-phosphogluconate (kdgp) and then cleaved by the aldolase encoded by the kdga gene. we cloned the kdga gene of the e. chrysanthemi strain 3937 by complementing an escherichia coli kdga mutation, using an rp4-derivative plasmid. restriction mapping of the kdga region and isolation of kdga-lac fusions allowed th ...	1994	8145647
expression of the butyrivibrio fibrisolvens endo-beta-1,4-glucanase gene together with the erwinia pectate lyase and polygalacturonase genes in saccharomyces cerevisiae.	recombinant saccharomyces cerevisiae strains capable of simultaneous secretion of bacterial glucanase and pectinase enzymes have been developed. the butyrivibrio fibrrisolvens endo-beta-1,4-glucanase gene (end1), the erwinia chrysanthemi pectate lyase gene (pele) and e. carotovora polygalacturonase gene (peh1) were each inserted between a yeast expression-secretion cassette and yeast gene terminator, and cloned into yeast-centromeric shuttle vectors. transcription initiation signals present in t ...	1994	7750141
identification of the integration host factor genes of erwinia chrysanthemi 3937.	two erwinia chrysanthemi homologues of the hima and himd genes of escherichia coli which encode the integration host factor (ihf) were cloned, sequenced and compared to their homolog in other enterobacteria (embl accession nos x74749 and x74750). both genes were inactivated by the insertion of an antibiotic resistance cassette, allowing for the isolation of ihf- mutants of e chrysanthemi.	1994	7748927
extracellular polysaccharide of erwinia chrysanthemi ech6.	many strains of erwinia chrysanthemi, which are gram-negative bacterial phytopathogens, produce copious amounts of extracellular polysaccharides. the extracellular polysaccharide from e. chrysanthemi pv. zeae strain sr 260, a phytopathogen of corn, is a branched-chain glucomannorhamnan of proven structure (gray et al., carbohydr. res. 1993, 245, 271-287). the extracellular polysaccharide from e. chrysanthemi ech6 is different, containing no rhamnose or mannose. it is composed of l-fucose, d-gala ...	1994	7727344
erwinia chrysanthemi and pseudomonas syringae: plant pathogens trafficking in extracellular virulence proteins.		1994	7859513
the three-dimensional structure of pectate lyase e, a plant virulence factor from erwinia chrysanthemi.	the three-dimensional structure of pectate lyase e (pele) has been determined by crystallographic techniques at a resolution of 2.2 a. the model includes all 355 amino acids but no solvent, and refines to a crystallographic refinement factor of 20.6%. the polypeptide backbone folds into a large right-handed cylinder, termed a parallel [beta] helix. loops of various sizes and conformations protrude from the central helix and probably confer function. a putative ca2+-binding site as well as two ca ...	1994	12232373
stimulation of berberine secretion and growth in cell cultures of thalictrum minus.	an endo-pectate lyase (pl; ec 4.2.2.2), originally cloned fiom the phytopathogenic bacterium erwinia chrysanthemi ec16, was expressed in reca (-) e. coli strain dk1, purified to a single band by isoelectric focusing and used to induce berberine production in established plant suspension cultures of thalictrum minus l. subsp. saxatile. addition of 10(-9)m pectate lyase c (plc) stimulated berberine production and enhanced secretion of the alkaloid into the medium. a lower concentration of plc, 10( ...	1994	24192880
the refined three-dimensional structure of pectate lyase c from erwinia chrysanthemi at 2.2 angstrom resolution (implications for an enzymatic mechanism).	the crystal structure of pectate lyase c (ec 4.2.2.2) from the enterobacterium erwinia chrysanthemi (pelc) has been refined by molecular dynamics techniques to a resolution of 2.2 a to an r factor of 17.97%. the final model consists of 352 of the total 353 amino acids and 114 solvent molecules. the root-mean-square deviation from ideality is 0.009 a for bond lengths and 1.768[deg] for bond angles. the structure of pelc bound to the lanthanide ion lutetium, used as a calcium analog, has also been ...	1995	12228363
genes required for cellulose synthesis in agrobacterium tumefaciens.	a region of the chromosome of agrobacterium tumefaciens 11 kb long containing two operons required for cellulose synthesis and a part of a gene homologous to the fixr gene of bradyrhizobium japonicum has been sequenced. one of the cellulose synthesis operons contained a gene (cela) homologous to the cellulose synthase (bsca) gene of acetobacter xylinum. the same operon also contained a gene (celc) homologous to endoglucanase genes from a. xylinum, cellulomonas uda, and erwinia chrysanthemi. the ...	1995	7860585
purification and characterization of an extracellular pectate lyase from an amycolata sp.	the extracellular pectate lyase (ec 4.2.2.2) of a nonsporulating amycolata sp. was purified to homogeneity by anion- and cation-exchange chromatographies followed by hydrophobic interaction chromatography. the enzyme cleaved polygalacturonate but not highly esterified pectin in a random endolytic transeliminative mechanism that led to the formation of a wide range of 4,5-unsaturated oligogalacturonates. as shown by high-performance anion-exchange chromatography and pulsed amperometric detection, ...	1995	7486993
functional implications of structure-based sequence alignment of proteins in the extracellular pectate lyase superfamily.	pectate lyases are plant virulence factors that degrade the pectate component of the plant cell wall. the enzymes share considerable sequence homology with plant pollen and style proteins, suggesting a shared structural topology and possibly functional relationships as well. the three-dimensional structures of two erwinia chrysanthemi pectate lyases, c and e, have been superimposed and the structurally conserved amino acids have been identified. there are 232 amino acids that superimpose with a ...	1995	7716248
flavohaemoglobin hmpx: a new pathogenicity determinant in erwinia chrysanthemi strain 3937.	unlike wild-type erwinia chrysanthemi strain 3937, which fully macerates inoculated saintpaulia plants, hmpx- mutants produce necrotic lesions or no symptoms. the hmpx gene was sequenced and the corresponding protein sequence analysed. we show that hmpx belongs to a family of flavohaemoproteins (hmp), previously identified in two yeasts and in escherichia coli. comparisons of protein sequences at the secondary structure level by hydrophobic cluster analysis have shown that hmpx possesses two fun ...	1995	7773389
the three genes lipb, lipc, and lipd involved in the extracellular secretion of the serratia marcescens lipase which lacks an n-terminal signal peptide.	the extracellular lipase of serratia marcescens sr41, lacking a typical n-terminal signal sequence, is secreted via a signal peptide-independent pathway. the 20-kb saci dna fragment which allowed the extracellular lipase secretion was cloned from s. marcescens by selection of a phenotype conferring the extracellular lipase activity on the escherichia coli cells. the subcloned 6.5-kb ecorv fragment was revealed to contain three open reading frames which are composed of 588, 443, and 437 amino aci ...	1995	7592412
gene cloning, sequence analysis, purification, and secretion by escherichia coli of an extracellular lipase from serratia marcescens.	the gene encoding extracellular lipase of serratia marcescens has been identified from a phage lambda genomic library. formation of orange-red fluorescent plaques on rhodamine b-triolein plates was used to identify phages carrying the lipase gene. a 2.8-kb sali fragment was subcloned into a plasmid, and lipase was expressed in escherichia coli. extracellular lipase was detected in the presence of the secretion plasmid pgsd6 carrying the genes prtd, -e, and -f, which guide the secretion of protea ...	1995	7618881
use of tn5tac1 to clone a pel gene encoding a highly alkaline, asparagine-rich pectate lyase isozyme from an erwinia chrysanthemi ec16 mutant with deletions affecting the major pectate lyase isozymes.	erwinia chrysanthemi mutant cucpb5047, delta(pela pele) delta(pelb pelc)::28bp delta(pelx) delta 4bp pehx::omega cmr, was constructed, mutated with tn5tac1, and screened for isopropyl-beta-d-thiogalactopyranoside-dependent pectate lyase (pel) production. a kmr saci fragment from the hyperexpressing pel+ mutant cucpb5066 was cloned into escherichia coli and sequenced. the gene identified, pell, encodes a novel, asparagine-rich, highly alkaline enzyme that is similar in primary structure to pelx a ...	1995	7635842
crystal structure of a complex between serratia marcescens metallo-protease and an inhibitor from erwinia chrysanthemi.	the crystal structure of the complex between the 50 kda metallo-endoproteinase from serratia marcescens (smp), a member of the metzincin superfamily, and an inhibitor from erwinia chrysanthemi (inh) was solved by molecular replacement using the known structure of smp, and refined at 2.30 a resolution to a crystallographic r-factor of 0.195. the e. chrysanthemi inhibitor folds into a compact eight-stranded antiparallel beta-barrel of simple up-down topology such as is found for members of the ret ...	1995	7752231
extracellular secretion of pullulanase is unaffected by minor sequence changes but is usually prevented by adding reporter proteins to its n- or c-terminal end.	linker insertions in the pullulanase structural gene (pula) were examined for their effects on pullulanase activity and cell surface localization in escherichia coli carrying the cognate secretion genes from klebsiella oxytoca. of the 23 insertions, 11 abolished pullulanase activity but none were found to prevent secretion. to see whether more drastic changes affected secretion, we fused up to five reporter proteins (e. coli periplasmic alkaline phosphatase, e. coli periplasmic maltose-binding p ...	1995	7665512
extracellular polysaccharide of erwinia chrysanthemi.		1995	7697648
cloning and sequencing of a 29 kb region of the bacillus subtilis genome containing the hut and wapa loci.	within the framework of an international project for the sequencing of the entire bacillus subtilis genome, a 29 kb chromosome segment, which contains the hut operon (335 degrees) and the wapa gene, has been cloned and sequenced. this region (28,954 bp) contains 21 complete orfs and one partial one. the 5th, 6th and 17th genes correspond to huth encoding histidase, hutp encoding the positive regulator for the hut operon and wapa encoding a precursor of three major wall-associated proteins, respe ...	1995	7704263
purification and characterization of the nuclease nucm of erwinia chrysanthemi.	the major periplasmic nuclease of erwinia chrysanthemi strain 3937, nucm, has been purified near to homogeneity by a one step purification procedure, using chromatography on a sulfopropyl column. nucm cleaves randomly single and double-stranded dna and rna. it does not need divalent cations for its action, and is more active in low salt buffers. a serine and a histidine residue could be present in the catalytic site. formation of disulfide bonds is necessary for nucm activity. nucm is probably s ...	1995	7599187
overproduction, purification and characterization of the cellulose-binding domain of the erwinia chrysanthemi secreted endoglucanase egz.	egz is the major endoglucanase secreted by erwinia chrysanthemi. functional characterization indicates that it is made of a catalytic n-terminal domain linked to a c-terminal cellulose-binding domain (cbd) by a ser/thr-rich linker. a chimeric plasmid, in which the cbd-encoding region was fused downstream of the ompa signal sequence, was constructed and introduced into escherichia coli. this allowed for the production of processed and disulfide-bonded cbd, mostly recovered from the culture supern ...	1995	7628464
differential effect of dsba and dsbc mutations on extracellular enzyme secretion in erwinia chrysanthemi.	an erwinia chrysanthemi gene able to complement an escherichia coli dsba mutation has been cloned and sequenced. this gene codes for a periplasmic protein with disulphide isomerase activity that has 69% identity and 94% similarity with the e. coli dsba protein. an e. chrysanthemi dsba-uida fusion mutant has been constructed. dsba expression seems to be constitutive. this mutant has multiple phenotypes resulting from the absence of disulphide bond formation in periplasmic and secreted proteins. p ...	1995	7476168
protein secretion by hybrid bacterial abc-transporters: specific functions of the membrane atpase and the membrane fusion protein.	the erwinia chrysanthemi metalloprotease c and the serratia marcescens haem acquisition protein hasa are both secreted from gram-negative bacteria by a signal peptide-independent pathway which requires a c-terminal secretion signal and a specific abc-transporter made up of three proteins: a membrane atpase (the abc-protein), a second inner membrane component belonging to the membrane fusion protein family and an outer membrane polypeptide. hasa and protease c transporters are homologous although ...	1995	7774588
cloning and characterization of the bgxa gene from erwinia chrysanthemi d1 which encodes a beta-glucosidase/xylosidase enzyme.	a beta-glucosidase/xylosidase gene from erwinia chrysanthemi strain d1 was cloned and sequenced. this gene, named bgxa, encodes a ca. 71 kda protein product which, following removal of the leader peptide, resulted in a ca. 69 kda mature protein that accumulated in the periplasmic space of e. chrysanthemi strain d1 and escherichia coli cells expressing the cloned gene. the protein exhibited both beta-glucosidase and beta-xylosidase activities but gave no detectable activity on xylan or carboxymet ...	1995	7891660
informational suppression to investigate structural functional and evolutionary aspects of the erwinia chrysanthemi cellulase egz.	the cellulase egz produced by the plant pathogen erwinia chrysanthemi belongs to family 5 of the beta-glycohydrolases (also referred to as cellulase family a), which contains over 40 members from gram-negative and gram-positive bacteria and fungi. amber mutations were introduced into 16 codons of the celz gene encoding egz. targeted residues included: (1) two glu, two his and one arg residue, strictly conserved throughout family 5; (2) one arg and one his residue conserved in sub-family 5-2; and ...	1995	7853408
effects of erwinia-asparaginase on the coagulation system.	l-asparaginase treatment during induction therapy in acute lymphoblastic leukaemia (all) is known to be frequently complicated by thromboembolic events. it was recently suggested that l-asparaginase derived from erwinia chrysanthemi alters the coagulation system less severely than does escherichia coli asparaginase. in a series of 11 adult patients with all, we investigated some parameters of the coagulation system during treatment with erwinia asparaginase. the doses employed were rather high; ...	1995	7493674
the effect of hetastarch on the stability of l-asparaginase during freeze-thaw cycling.	l-asparaginase, a therapeutic agent for the treatment of acute lymphoblastic leukemia, was evaluated for its susceptibility to cold denaturation. it was found that the enzyme derived from erwinia chrysanthemi loses its activity when exposed to freeze-thaw cycling. when it was frozen at -40 degrees c and thawed, the enzyme lost 67.3% of its activity; whereas, when frozen in liquid nitrogen (-190 degrees c), it lost almost all of its activity. rheological studies of hetastarch showed that its visc ...	1995	7542144
use of recombinase gene fusions to identify vibrio cholerae genes induced during infection.	a complete understanding of host-parasite interactions must necessarily include the identification and characterization of gene products expressed by both parties during the infectious process. we have developed a new screen to identify bacterial genes that are transcriptionally induced during infection of a host animal. the method is based on pre-selection of strains carrying tnpr operon fusions (encoding resolvase, a site-specific dna recombinase) which are not expressed in vitro, followed by ...	1995	8817490
polymerase chain reaction for verification of fluorescent colonies of erwinia chrysanthemi and pseudomonas putida wcs358 in immunofluorescence colony staining.	the potential of polymerase chain reaction (pcr) for verifying the identity of colonies stained by the immunofluorescence colony-staining (ifc) procedure was investigated. using primers directed against conserved sequences of the pectate lyase-genes coding for isozymes pla, pld and ple of erwinia chrysanthemi, the authors confirmed the identity of 96% of 20 fluorescent target colonies, punched from ifc-stained samples with pure cultures. in pour plates with mixtures of erw. chrysanthemi and non- ...	1995	8567494
characterization of the pell gene encoding a novel pectate lyase of erwinia chrysanthemi 3937.	erwinia chrysanthemi 3937 secretes five major isoenzymes of pectate lyases encoded by the pela, pelb, pelc, peld and pele genes. recently, a new set of pectate lyases was identified in e. chrysanthemi mutants deleted of those pel genes. we cloned the pell gene, encoding one of these secondary pectate lyases of e. chrysanthemi 3937, from a genomic bank of a strain deleted of the five major pel genes. the nucleotide sequence of the region containing the pell gene was determined. the pell reading f ...	1995	8577252
erwinia chrysanthemi harpinech: an elicitor of the hypersensitive response that contributes to soft-rot pathogenesis.	mutants of the soft-rot pathogen erwinia chrysanthemi ec16 that are deficient in the production of the pectate lyase isozymes pelabce can elicit the hypersensitive response (hr) in tobacco leaves. the hrpnech gene was identified in a collection of cosmids carrying e. chrysanthemi hrp genes by its hybridization with the erwinia amylovora hrpnea gene. hrpnech appears to be in a monocistronic operon, and it encodes a predicted protein of 340 amino acids that is glycine-rich, lacking in cysteine, an ...	1995	8589405
differential expression of two siderophore-dependent iron-acquisition pathways in erwinia chrysanthemi 3937: characterization of a novel ferrisiderophore permease of the abc transporter family.	in planta expression of a high-affinity iron-uptake system involving the siderophore chrysobactin in erwinia chrysanthemi 3937 contributes greatly to invasive growth of this pathogen on its natural host, african violets. a previous study reported that global regulation by iron in this strain was mediated at the transcriptional level via the cbr locus which, when inactivated by insertional mutation, prevents the chrysobactin system from being tightly repressed by fecl3. herein, we report the nucl ...	1995	8596459
"horizontal" gene transfer from a transgenic potato line to a bacterial pathogen (erwinia chrysanthemi) occurs--if at all--at an extremely low frequency.	the frequency of possible "horizontal" gene transfer between a plant and a tightly associated bacterial pathogen was studied in a model system consisting of transgenic solanum tuberosum, containing a beta-lactamase gene linked to a pbr322 origin of replication, and erwinia chrysanthemi. this experimental system offers optimal conditions for the detection of possible horizontal gene transfer events, even when they occur at very low frequency. horizontal gene transfer was not detected under condit ...	1995	9636282
purification of an l-asparaginase-atrial natriuretic peptide fusion protein expressed in escherichia coli.	a novel fusion protein designed to facilitate protein purification was expressed in escherichia coli and purified separately by two different chromatography methods. l-asparaginase from erwinia chrysanthemi is fused to the n-terminus of a model peptide, alpha-human atrial natriuretic peptide (alpha-hanp). l-asparaginase was chosen because of its selective affinity for l-asparagine and because of its unusually high isoelectric point(8.6). a gene construction without the l-asparaginase native sign ...	1995	18623425
the role of iron in plant host-pathogen interactions.	iron is unlikely to be readily available in plant tissues for invading microorganisms. soft rot, caused by erwinia chrysanthemi strain 3937 on african violets, is a valuable model for studying the role of iron and its ligands in plant-pathogen interactions. these studies could lead to the development of new control strategies against microbial infections of plants.	1996	8795159
complementation of deletion mutations in a cloned functional cluster of erwinia chrysanthemi out genes with erwinia carotovora out homologues reveals outc and outd as candidate gatekeepers of species-specific secretion of proteins via the type ii pathway.	the type ii or sec-dependent secretion system is used by diverse gram-negative bacteria for secretion of extracellular proteins. of the 12-15 proteins involved in secretion, the requirement for many has not been demonstrated and little is known about their functions in the secretion process. the plant pathogens erwinia chrysanthemi and erwinia carotovora secrete extra-cellular pectate lyases (pels) using the type ii or out pathway. however, these two bacteria cannot secrete pels encoded by heter ...	1996	8861215
role of lysine, tryptophan and calcium in the beta-elimination activity of a low-molecular-mass pectate lyase from fusarium moniliformae.	an extracellular pectate lyase from fusarium moniliformae was purified to homogeneity by affinity chromatography followed by gel filtration, with a yield of 76.5%. laser desorption ms of the enzyme gave a molecular mass of 12,133.5 +/- 2.5 da. the pectate lyase was a glycoprotein with a 5% carbohydrate content and had a pl value of 9.1. atomic-emission spectrometry showed that ca2+ was a part of the holoenzyme held by carboxy groups of the protein. these results support the hypothesis of a putat ...	1996	8870663
purification and functional characterization of pecs, a regulator of virulence-factor synthesis in erwinia chrysanthemi.	the erwinia chrysanthemi pecs gene encodes a repressor that negatively regulates the expression of virulence factors such as pectinases or cellulases. the cloned pecs gene was overexpressed using a phage t7 system. the purification of pecs involved deae-anion exchange and tsk-heparin columns and delivered the pecs protein that was purified to homogeneity. the purified repressor displayed an 18 kda apparent molecular mass and an isoelectric point near to neutrality (pl = 6.5). gel-filtration expe ...	1996	8733237
differential effect of site-directed mutations in pelc on pectate lyase activity, plant tissue maceration, and elicitor activity.	oligonucleotide site-directed mutations were introduced into the pelc gene of erwinia chrysanthemi ec16 that directed single or double amino acid changes affecting disulfide linkages, calcium binding, catalysis, and protein folding. subsequent characterization of the purified pelc mutant proteins demonstrated that pectinolytic function involves amino acids located near the calcium binding site rather than those surrounding an invariant vwidh sequence. wild-type pelc and the tested mutant protein ...	1996	8900122
l-asparagine depletion in plasma and cerebro-spinal fluid of children with acute lymphoblastic leukemia during subsequent exposures to erwinia l-asparaginase.	monitoring l-asparagine (l-asn) plasma levels could provide information useful for determining whether the dosage or schedule of l-asparaginase (l-ase) administration is adequate. very few data are available on depletion caused by the erwinia chrysanthemi (e. chrysanthemi) product. since it has been suggested that l-asn depletion may have been overestimated in the past due to residual l-ase activity, samples in this study have been analyzed after deproteinization with sulphosalicylic acid. patie ...	1996	8905031
regulation of pectinolysis in erwinia chrysanthemi.	erwinia chrysanthemi is an enterobacterium that causes various plant diseases. its pathogenicity results from the secretion of pectinolytic enzymes responsible for the disorganization of the plant cell wall. the e. chrysanthemi strain 3937 produces two pectin methylesterases, at least seven pectate lyases, a polygalacturonase, and a pectin lyase. the extracellular degradation of the pectin leads to the formation of oligogalacturonides that are catabolized through an intracellular pathway. the pe ...	1996	8905080
an in vivo pathway for disulfide bond isomerization in escherichia coli.	biochemical studies have shown that the periplasmic protein disulfide oxidoreductase dsbc can isomerize aberrant disulfide bonds. here we present the first evidence for an in vivo role of dsbc in disulfide bond isomerization. furthermore, our data suggest that the enzymes dsba and dsbc play distinct roles in the cell in disulfide bond formation and isomerization, respectively. we have shown that mutants in dsbc display a defect in disulfide bond formation specific for proteins with multiple disu ...	1996	8917542
protein secretion in gram-negative bacteria: assembly of the three components of abc protein-mediated exporters is ordered and promoted by substrate binding.	one of the strategies used by gram-negative bacteria to secrete proteins across the two membranes which delimit the cells, is sec independent and dedicated to proteins lacking an n-terminal signal peptide. it depends on abc protein-mediated exporters, which consist of three cell envelope proteins, two inner membrane proteins, an atpase (the abc protein), a membrane fusion protein (mfp) and an outer membrane polypeptide. erwinia chrysanthemi metalloproteases b and c and serratia marcescens hemopr ...	1996	8918458
cloning of the serratia marcescens hasf gene encoding the has abc exporter outer membrane component: a tolc analogue.	the serratia marcescens haemophore hasa is secreted by an abc exporter comprising three envelope proteins. the abc protein (atp-binding cassette) hasd and the mfp protein (membrane fusion protein) hase but not the outer membrane component have been isolated previously. in escherichia coli, tolc, the outer membrane component of the haemolysin transporter, can form a hybrid exporter with hasd and hase. this hybrid secretes hasa and the very similar metalloproteases from s. marcescens and erwinia c ...	1996	8930911
regulation of pelz, a gene of the pelb-pelc cluster encoding a new pectate lyase of erwinia chrysanthemi 3937.	the phytopathogenic enterobacterium erwinia chrysanthemi 3937 produces five major and several secondary endo-pectate lyases encoded by the pel genes. most of these genes are arranged in clusters on the bacterial chromosome. the genomic region surrounding the pelb-pelc cluster was supposed to be involved in the regulation of pelb and pelc synthesis. we demonstrated that the variation of pelb expression resulted from the titration of a regulatory protein by the gene adjacent to pelc. this gene was ...	1996	8955401
the secretin-specific, chaperone-like protein of the general secretory pathway: separation of proteolytic protection and piloting functions.	the chaperone-like protein of the main terminal branch of the general secretory pathway from klebsiella oxytoca, the outer membrane lipoprotein puls, protects the multimeric secretin puld from degradation and promotes its correct localization to the outer membrane. to determine whether these are separable functions, or whether resistance to proteolysis results simply from correct localization of puld, we replaced the lipoprotein-type signal peptide of puls by the signal peptide of periplasmic ma ...	1996	8971717
the erwinia chrysanthemi pect gene regulates pectinase gene expression.	a new type of erwinia chrysanthemi mutant displaying a derepressed synthesis of pectate lyase was isolated. the gene mutated in these strains, pect, encodes a 316-amino-acid protein with a size of 34,761 da that belongs to the lysr family of transcriptional activators and presents 61% identity with the e. coli protein lrha. pect represses the expression of pectate lyase genes pelc, peld, pele, pell, and kdgc, activates pelb, and has no effect on the expression of pela or the pectin methylesteras ...	1996	8626286
characterization of erwinia chrysanthemi by pectinolytic isozyme polymorphism and restriction fragment length polymorphism analysis of pcr-amplified fragments of pel genes.	conserved regions about 420 bp long of the pelade cluster specific to erwinia chrysanthemi were amplified by pcr and used to differentiate 78 strains of e. chrysanthemi that were obtained from different hosts and geographical areas. no pcr products were obtained from dna samples extracted from other pectinolytic and nonpectinolytic species and genera. the pel fragments amplified from the e. chrysanthemi strains studied were compared by performing a restriction fragment length polymorphism (rflp) ...	1996	8779560
characterization of pectin methylesterase b, an outer membrane lipoprotein of erwinia chrysanthemi 3937.	the secretion of extracellular pectinases, among which there are least six isoenzymes of pectate lyase and one pectin methylesterase, allows the phytopathogenic bacterium erwinia chrysanthemi to degrade pectin. a gene coding for a novel pectin methylesterase has been cloned from an e. chrysanthemi strain 3937 gene library. this gene, pemb, codes for a 433-amino-acid protein. the pemb n-terminal region has the characteristics of lipoprotein signal sequences. we have shown that the pemb precursor ...	1996	8830237
synthesis of optically pure chrysobactin and immunoassay development.	chrysobactin (alpha-n-(2,3-dihydroxybenzoyl)-d-lysyl-l-serine), a siderophore that is essential for systemic virulence by plant pathogenic erwinia chrysanthemi, was synthesized with high diastereomeric purity. chrysobactin was prepared by coupling the n-hydroxysuccinimide ester of alpha-n-(2,3-dibenzyloxybenzoyl)-epsilon-n-cbz-d-lysine with l-serine benzyl ester followed by deprotection via hydrogenolysis. optically pure chrysobactin was obtained with 98% overall yield. a monoclonal antibody to ...	1996	8837459
analysis of the erwinia chrysanthemi ferrichrysobactin receptor gene: resemblance to the escherichia coli fepa-fes bidirectional promoter region and homology with hydroxamate receptors.	the fct cbsceba operon from the erwinia chrysanthemi 3937 chrysobactin-dependent iron assimilation system codes for transport and biosynthetic functions. the sequence of the fct outer membrane receptor gene was determined. the fct promoter region displays a strong resemblance to the escherichia coli bidirectional intercistronic region controlling the expression of the fepa-entd and fes-entf operons. an apparent fur-binding site was shown to confer iron regulation on an fct::lac fusion expressed ...	1996	8576065
cloning and characterization of a xylanase gene from corn strains of erwinia chrysanthemi.	the gene encoding a 42-kda endoxylanase was cloned from erwinia chrysanthemi strain d1. sequencing of this gene, called xyna, showed that it encoded a primary protein product of 413 amino acids with an unusual and long (31 amino acid) leader peptide that was cleaved during secretion to the bacterial periplasm. this protein is distinct from xylanases in glycohydrolase families 10 and 11 and, instead, appears to be intermediate between families 5 and 30. the xyna gene is located downstream from a ...	1996	8810080
characterization of the erwinia chrysanthemi osmoprotectant transporter gene ousa.	growth of erwinia chrysanthemi in media of elevated osmolarity can be achieved by the uptake and accumulation of various osmoprotectants. this study deals with the cloning and sequencing of the ousa gene-encoded osmoprotectant uptake system a from e. chrysanthemi 3937. ousa belongs to the superfamily of solute ion cotransporters. this osmotically inducible system allows the uptake of glycine betaine, proline, ectoine, and pipecolic acid and presents strong similarities in nucleotide sequence and ...	1996	8550465
regulatory systems modulating the transcription of the pectinase genes of erwinia chrysanthemi are conserved in escherichia coli.	to depolymerize plant pectin, the phytopathogenic enterobacterium erwinia chrysanthemi produces five isoenzymes of pectate lyases encoded by the five genes pela, pelb, pelc, peld and pele. in er. chrysanthemi, all genes involved in pectin degradation are specifically controlled by the kdgr repressor and are induced in the presence of a pectin catabolic product, 2-keto-3-deoxygluconate (kdg). transcription of the pectinase genes is dependent on many environmental conditions. transcriptional fusio ...	1996	8828230
the refined three-dimensional structure of pectate lyase e from erwinia chrysanthemi at 2.2 a resolution.	the crystal structure of pectate lyase e (pele; ec 4.2.2.2) from the enterobacteria erwinia chrysanthemi has been refined by molecular dynamics techniques to a resolution of 2.2 a and an r factor (an agreement factor between observed structure factor amplitudes) of 16.1%. the final model consists of all 355 amino acids and 157 water molecules. the root-mean-square deviation from ideality is 0.009 a for bond lengths and 1.721[deg] for bond angles. the structure of pele bound to a lanthanum ion, w ...	1996	12226275
comparison of extracellular polysaccharides of erwinia chrysanthemi spp.	two extracellular polysaccharides from strains of erwinia chrysanhemi ech 1 and 9, phytopathogens of potatoes, have been isolated and purified. both have similar compositions and other properties to that produced by strain sr 260, a phytopathogen of corn. these polysaccharides are composed of l-rhamnose, d-mannose, d-glucose, d-glucuronic acid in the ratio 3:1:1:1. initial structural aspects of these polysaccharides are reflected in the 600 mhz 1h nmr spectra and the products of partial acid hyd ...	1996	8910063
cloning, sequence and expression of the pel gene from an amycolata sp.	the pel gene from an amycolata sp. encoding a pectate lyase (ec 4.2.2.2) was isolated by activity screening a genomic dna library in streptomyces lividans tk24. subsequent subcloning and sequencing of a 2.3 kb bamhi bglii fragment revealed an open reading frame of 930 nt corresponding to a protein of 29,660 da. the overall g + c content for the coding region was 65%, with a strong g + c preference in the third (wobble) codon position (93%). a putative ribosome-binding site 5'-gggag-3' preceded t ...	1997	9427544
use of model plant hosts to identify pseudomonas aeruginosa virulence factors.	we used plants as an in vivo pathogenesis model for the identification of virulence factors of the human opportunistic pathogen pseudomonas aeruginosa. nine of nine tnphoa mutant derivatives of p. aeruginosa strain ucbpp-pa14 that were identified in a plant leaf assay for less pathogenic mutants also exhibited significantly reduced pathogenicity in a burned mouse pathogenicity model, suggesting that p. aeruginosa utilizes common strategies to infect both hosts. seven of these nine mutants contai ...	1997	9371831
solution structure of the cellulose-binding domain of the endoglucanase z secreted by erwinia chrysanthemi.	two-dimensional proton nuclear magnetic resonance spectroscopy has been used to determine the three-dimensional structure of the 62 amino acid c-terminal cellulose-binding domain (cbd) of the endoglucanase z (cbdegz), secreted by erwinia chrysanthemi. an experimental data set comprising 958 interproton noe-derived restraints was used to calculate 23 structures. the calculated structures have an average root-mean-square deviation between cys4 and cys61 of 0.91 +/- 0.11 a for backbone atoms and 1. ...	1997	9405041
identification of a bacterial pectin acetyl esterase in erwinia chrysanthemi 3937.	erwinia chrysanthemi causes soft-rot diseases of various plants by enzymatic degradation of the pectin in plant cell walls. the structural complexity of pectin requires the combined action of several pectinases for its efficient breakdown. three types of pectinases have so far been identified in e. chrysanthemi: two pectin methyl esterases (pema, pemb), a polygalacturonase (pehx), and eight pectate lyases (pela, pelb, pelc, peld, pele, pell, pelz, pelx). we report in this paper the analysis of a ...	1997	9218776
the rhizobium leguminosarum prsde genes are required for secretion of several proteins, some of which influence nodulation, symbiotic nitrogen fixation and exopolysaccharide modification.	nodo is a secreted protein from rhizobium leguminosarum bv. viciae with a role in signalling during legume nodulation. a tn5-induced mutant was identified that was defective in nodo secretion. as predicted, the secretion defect decreased pea and vetch nodulation but only when the node gene was also mutated. this confirms earlier observations that nodo plays a particularly important role in nodulation when nod factors carrying c18:1 (but not c18:4) acyl groups are the primary signalling molecules ...	1997	11902716
spectroscopic studies of the c-terminal secretion signal of the serratia marcescens haem acquisition protein (hasa) in various membrane-mimetic environments.	the structure of a peptide comprising the last 56 c-terminal residues of the serratia marcescens haem acquisition protein (hasa) secreted by an atp-binding cassette exporter was examined by 1h-nmr, circular dichroic and fluorescence spectroscopies. the peptide, which contains the secretion signal of hasa, is efficiently secreted by the hasa transporter. it is largely unstructured and flexible in aqueous buffer solution, but its helical content increases upon addition of trifluoroethanol, deterge ...	1997	9030765
antitermination of transcription of catabolic operons.	antitermination of transcription mediated by proteins interacting with mrna sequences is described for nine operons/regulons. eight of the systems are catabolic, while the ninth, the klebsiella pneumoniae nas regulon, is involved in the assimilation of nitrate and nitrite. six of the catabolic operons/regulons are found in bacillus subtilis, one is found in escherichia coli, and one in pseudomonas aeruginosa. the antitermination system of five of the operons/regulons (e. coli blg, and sacpa, sac ...	1997	9044276
the lac operon of lactobacillus casei contains lact, a gene coding for a protein of the bg1g family of transcriptional antiterminators.	the 5' region of the lac operon of lactobacillus casei has been investigated. an open reading frame of 293 codons, designated lact, was identified upstream of lace. the gene product encoded by lact is related to the family of transcriptional antiterminator proteins, which includes bglg from escherichia coli, arbg from erwinia chrysanthemi, sact, sacy, and lict from bacillus subtilis, and bglr from lactococcus lactis. amino acid sequence identities range from 35 to 24%, while similarities range f ...	1997	9045813
extracellular melibiose and fructose are intermediates in raffinose catabolism during fermentation to ethanol by engineered enteric bacteria.	contrary to general concepts of bacterial saccharide metabolism, melibiose (25 to 32 g/liter) and fructose (5 to 14 g/liter) accumulated as extracellular intermediates during the catabolism of raffinose (o-alpha-d-galactopyranosyl-1, 6-alpha-d-glucopyranosyl-beta-d-fructofuranoside) (90 g/liter) by ethanologenic recombinants of escherichia coli b, klebsiella oxytoca m5a1, and erwinia chrysanthemi ec16. both hydrolysis products (melibiose and fructose) were subsequently transported and further me ...	1997	9068632
antagonistic effect of crp and kdgr in the transcription control of the erwinia chrysanthemi pectinolysis genes.	the main virulence factors of the phytopathogenic bacteria erwinia chrysanthemi are pectinases that cleave pectin, a major constituent of the plant cell wall. the cyclic amp receptor protein (crp) was identified as the main activator of the pectinolysis genes. gel shift and dnase i footprinting experiments showed that the purified e. chrysanthemi crp protein binds specifically to the promoter regions of seven pectinolysis genes (pelb, pelc, peld, pele, ogl, kdui and kdgt) whose expression is pos ...	1997	9426143
pharmacokinetics and drug monitoring of l-asparaginase treatment.	the enzyme l-asparaginase is an important component of the treatment protocols for acute lymphoblastic leukemia (all). this enzyme is derived from different biological sources (e. coli and erwinia chrysanthemi). an increasing number of hemorrhagic and thrombotic events prompted us to initiate a monitoring program for asparaginase treatment. different asparaginase preparations were monitored in children on the all-bfm induction and reinduction treatment (10,000 u/m2 every 3-4 days). the different ...	1997	9088996
phylogenetic analysis of erwinia species based on 16s rrna gene sequences.	the phylogenetic relationships of the type strains of 16 erwinia species were investigated by performing a comparative analysis of the sequences of the 16s rrna genes of these organisms. the sequence data were analyzed by the neighbor-joining method, and each branch was supported by moderate bootstrap values. the phylogenetic tree and sequence analyses confirmed that the genus erwinia is composed of species that exhibit considerable heterogeneity and form four clades that are intermixed with mem ...	1997	9336906
bacterial flavohaemoglobins: a consensus sequence and identification of a discrete enterobacterial group and of further bacterial globins.	the amino acid sequences of haemoglobin-like proteins from the bacteria alcaligenes eutrophus, bacillus subtilis, erwinia chrysanthemi, escherichia coli, vibrio parahaemolyticus, vitreoscilla sp. and the yeast saccharomyces cerevisiae were studied. phylogenies based on distance and parsimony analysis showed that the eubacterial group can be easily distinguished from the other haemoglobin-like proteins. the construction of a consensus bacterial flavohaemoglobin based on the alignment of six bacte ...	1997	9351199
identification of genes in rhizobium leguminosarum bv. trifolii whose products are homologues to a family of atp-binding proteins.	the specific interaction between rhizobia and their hosts requires many genes that influence both early and late steps in symbiosis. three new genes, designated prsd, prse (protein secretion) and orf3, were identified adjacent to the exo133 mutation in a cosmid carrying the genomic dna of rhizobium leguminosarum bv. trifolii ta1. the prsde genes share significant homology to the genes encoding abc transporter proteins prtde from erwinia chrysanthemi and aprde from pseudomonas aeruginosa which ex ...	1997	9141701
mutual control of the pecs/pecm couple, two proteins regulating virulence-factor synthesis in erwinia chrysanthemi.	the erwinia chrysanthemi pecs mutant displays constitutive production of virulence factors, such as pectinases or cellulases. complementation of the pecs mutation can be obtained in the presence of the pecs wild-type gene on a low-copy-number plasmid. moreover, the resulting plasmid decreases the expression of a pecs::uida chromosomal fusion, indicating the existence of an autoregulation mechanism. this negative autoregulation was confirmed and quantified by analysis of the pecs transcripts usin ...	1997	9194707
the cyclic amp receptor protein is the main activator of pectinolysis genes in erwinia chrysanthemi.	the main virulence factors of the phytopathogenic bacterium erwinia chrysanthemi are pectinases that cleave pectin, a major constituent of the plant cell wall. although physiological studies suggested that pectinase production in erwinia species is subjected to catabolite repression, the direct implication of the cyclic amp receptor protein (crp) in this regulation has never been demonstrated. to investigate the role of crp in pectin catabolism, we cloned the e. chrysanthemi crp gene by compleme ...	1997	9171393
detection of rtx toxin genes in gram-negative bacteria with a set of specific probes.	the family of rtx (rtx representing repeats in the structural toxin) toxins is composed of several protein toxins with a characteristic nonapeptide glycine-rich repeat motif. most of its members were shown to have cytolytic activity. by comparing the genetic relationships of the rtx toxin genes we established a set of 10 gene probes to be used for screening as-yet-unknown rtx toxin genes in bacterial species. the probes include parts of apxia, apxiia, and apxiiia from actinobacillus pleuropneumo ...	1997	9172345
specific interaction between outd, an erwinia chrysanthemi outer membrane protein of the general secretory pathway, and secreted proteins.	outd is an outer membrane component of the main terminal branch of the general secretory pathway (gsp) in erwinia chrysanthemi. we analyzed the interactions of outd with other components of the gsp (out proteins) and with secreted proteins (pelb, egz and pema). outd is stabilized by its interaction with another gsp component, outs. the 62 c-terminal amino acids of outd are necessary for this interaction. in vivo formation of outd multimers, up to tetramers, was proved after the dissociation in m ...	1997	9214618
protein secretion by gram-negative bacterial abc exporters.	one of the strategies used by gram-negative bacteria to secrete proteins across the two membranes which delimit the cells, is sec independent and dedicated to proteins lacking an n-terminal signal peptide. it depends on abc protein-mediated exporters, which consist of three cell envelope proteins: two inner membrane proteins: an atpase (the abc protein), a membrane fusion protein (mfp) and an outer membrane polypeptide. erwinia chrysanthemi metalloproteinases b and c, and serratia marcescens hem ...	1997	9246759
longus pilus of enterotoxigenic escherichia coli and its relatedness to other type-4 pili--a minireview.	longus is a long pilus produced by human enterotoxigenic escherichia coli (etec) which shares significant structural and biochemical features with class-b type-4 pili. these pili include the toxin-coregulated pilus (tcp) of vibrio cholerae, the bundle-forming pilus (bfp) of enteropathogenic e. coli and both longus and the colonization factor antigen iii (cfa/iii) of etec. these pili are produced under defined growth conditions indicating that they are under the control of different regulatory el ...	1997	9224872
lipase secretion by bacterial hybrid atp-binding cassette exporters: molecular recognition of the lipbcd, prtdef, and hasdef exporters.	serratia marcescens secretes several proteins, such as the lipase lipa, the metalloprotease prta, and the heme-binding protein hasa, which is required for heme acquisition, through two n-terminal signal peptide-independent systems that are classified as bacterial atp-binding cassette (abc) exporters. one is the abc exporter for hasa, consisting of the abc protein hasd, the membrane fusion protein (mfp) hase, and the outer membrane protein (omp) hasf. the second, composed of lipb (an abc protein) ...	1997	9244262
investigation of physicochemical changes to l-asparaginase during freeze-thaw cycling.	l-asparaginase derived from erwinia chrysanthemi which is being investigated as an alternative to e. coli for the treatment of lymphoblastic leukaemia has been found in our laboratory to lose activity upon exposure to consecutive freeze-thaw cycles. an investigation was undertaken using several techniques to characterize fully the physicochemical changes l-asparaginase is undergoing during freeze-thaw cycling leading to the loss of its activity. a total protein assay suggested that the loss of s ...	1997	9178179
comparative analysis of the five major erwinia chrysanthemi pectate lyases: enzyme characteristics and potential inhibitors.	in erwinia chrysanthemi 3937, pectate lyase activity mainly results from the cumulative action of five major isoenzymes, pela to pele. comparison of their amino acid sequences revealed two families, pelb-c and pela-d-e. molecular cloning permitted expression of the different pel genes in escherichia coli and the isolation of each pel independently from the other isoenzymes. we used similar experimental conditions to overproduce and purify the five pels in a one-step chromatography method. we ana ...	1997	9098045
molecular cloning, characterization, and mutagenesis of a pel gene from pseudomonas syringae pv. lachyrmans encoding a member of the erwinia chrysanthemi pelade family of pectate lyases.	the pels gene from pseudomonas syringae pv. lachrymans 859 was cloned by heterologous expression in nonpectolytic p. syringae pv. syringae buvs1, using genomic dna libraries constructed with two novel broad-host-range cosmid vectors, pcpp34 and pcpp47. screening of p. syringae pv. syringae transconjugants for the ability to pit pectate media at ph 6.0 and 8.5 yielded several overlapping clones of the same dna region. ultrathin-layer isoelectric focusing gels, activity-stained with diagnostically ...	1997	9100381
the pecm protein is necessary for the dna-binding capacity of the pecs repressor, one of the regulators of virulence-factor synthesis in erwinia chrysanthemi.	the pecs regulatory locus is responsible for the down-expression of many virulence genes in erwinia chrysanthemi. this locus consists of two genes, pecs and pecm, divergently transcribed. genetic evidence indicates that the pecm protein modulates the regulatory activity of pecs. purification and characterization of pecs, expressed either from e. coli, from the wild-type e. chrysanthemi strain or from a pecm mutant, showed that the pecs protein produced in these three genetic backgrounds displays ...	1997	9311123
pectate lyase peli of erwinia chrysanthemi 3937 belongs to a new family.	erwinia chrysanthemi 3937 secretes five major isoenzymes of pectate lyases encoded by the pel4, pelb, pelc, peld, and pele genes and a set of secondary pectate lyases, two of which, pell and pelz, have been already identified. we cloned the peli gene, encoding a ninth pectate lyase of e. chrysanthemi 3937. the peli reading frame is 1,035 bases long, corresponding to a protein of 344 amino acids including a typical amino-terminal signal sequence of 19 amino acids. the purified mature peli protein ...	1997	9393696
protein secretion by gram-negative bacterial abc exporters--a review.	one of the strategies used by gram-negative bacteria to secrete proteins across the two membranes which delimit the cells is sec-independent and dedicated to proteins lacking an n-terminal signal peptide. most of these proteins display a c-terminal secretion signal located in the last 60 amino acids (aa). using one erwinia chrysanthemi protease, prtg, secreted by such a pathway it was shown that the smallest c-terminal sequence allowing efficient secretion contains the last 29 aa of prtg and tha ...	1997	9224868
an exo-poly-alpha-d-galacturonosidase, pehb, is required for wild-type virulence of ralstonia solanacearum.	ralstonia solanacearum, which causes bacterial wilt disease of many plant species, produces several extracellular plant cell wall-degrading enzymes that are suspected virulence factors. these include a previously described endopolygalacturonase (pg), peha, and two exo-pgs. a gene encoding one of the exo-pgs, pehb, was cloned from r. solanacearum k60. the dna fragment specifying pehb contained a 2,103-bp open reading frame that encodes a protein of 74.2 kda with a typical n-terminal signal sequen ...	1997	9393701
characterization of a periplasmic peptidyl-prolyl cis-trans isomerase in erwinia chrysanthemi.	the main determinant of the plant pathogen erwinia chrysanthemi virulence is the production of extracellular enzymes, mainly pectate lyases. adjacent to a pectate lyase encoding locus, we identified the gene rota supposed to encode a folding catalyst. overproduction of the protein and assay of activity using a synthetic substrate, confirmed that rota encodes a periplasmic peptidyl-prolyl cis-trans isomerase. rota disruption provokes no change in cell morphology, cell viability, growth rate or st ...	1997	9418240
characterization of the pect control region from erwinia chrysanthemi 3937.	erwinia chrysanthemi synthesizes and secretes pectate lyases that attack components of the plant cell wall and, therefore, play a major role in the pathogenesis of soft rot disease. we isolated a new mutant (designated pec-1), by tn5 mutagenesis, that displays weak pectate lyase production and decreased motility and mucoidicity. maceration and pathogenicity tests done on different plant organs showed that the pec-1 strain displays a reduced virulence compared to that of the parental strain. the ...	1997	9244282
in vitro and in vivo redox states of the escherichia coli periplasmic oxidoreductases dsba and dsbc.	dsbc is a periplasmic protein of escherichia coli that was previously identified by a genetic selection that rescued sensitivity to dithiothreitol in tn10 mutagenized cells. the erwinia chrysanthemi dsbc gene was identified in a previous genetic screen to restore motility in a dsba null strain. in order to analyze the biochemical role of e. coli dsbc, the protein was overexpressed, purified, and compared with dsba in terms of disulfide isomerization, thiol oxidation, and in vivo redox state. in ...	1997	9254601
production of recombinant bacterial endoglucanase as a co-product with ethanol during fermentation using derivatives of escherichia coli ko11.	this study demonstrates a new approach to reduce the amount of fungal cellulase required for the conversion of cellulose into ethanol. escherichia coli ko11, a biocatalyst developed for the fermentation of hemicellulose syrups, was used to produce recombinant endoglucanase as a co-product with ethanol. seven different bacterial genes were expressed from plasmids in ko11. all produced cell-associated endoglucanase activity. ko11(ploi1620) containing erwinia chrysanthemi celz (egz) produced the hi ...	1997	18636522
[in process citation].	the cure rate for children with acute lymphoblastic leukaemia (all) has increased to approximately 70%, in part related to the use of the protein synthesis inhibitor drug asparaginase in multiagent chemotherapy regimens. its lack of haematological toxicity allows its incorporation into phases of therapy in which myelosuppression would be expected either from the disease itself (induction therapy) or secondary to other chemotherapeutic agents (consolidation, intensification or reinduction phases ...	1997	18031078
crystallization and preliminary x-ray crystallographic analysis of shikimate kinase from erwinia chrysanthemi.	shikimate kinase from erwinia chrysanthemi, overexpressed in escherichia coli has been crystallized by the vapour-diffusion method using sodium chloride as a precipitant. mass spectrometry was used to confirm the purity of the shikimate kinase and dynamic light scattering was used to assess conditions for the monodispersity of the enzyme. the crystals are tetragonal, space group p4(1)2(1)2 or enantiomorph with cell dimensions a = b = 108.5 and c = 92.8 a (at 100 k). native crystals diffract to b ...	1997	15299895
crystallization of xylanase from erwinia chrysanthemi: influence of heat and polymeric substrate.	xylanase from the bacterial plant pathogen erwinia chrysanthemi (e.c. 3.2.1.8), expressed in e. coli, has been crystallized for x-ray diffraction analysis both in the presence and the absence of its polymeric substrate 4-o-methyl glucuronoxylan. in all cases it was found that the quality, time of appearance, and reproducibility of both the native and complex crystals were significantly enhanced by heating of the protein to 323 k prior to dispensing the crystallization trials. crystals of the nat ...	1997	15299927
crystallization of cytochrome b562 from erwinia chrysanthemi.	cytochrome b(562) from erwinia chrysanthemi has been crystallized using the hanging-drop vapour-diffusion method with ammonium sulfate as the precipitant. x-ray precession photographs show that the crystals formed belong to either of the enantiomorphic space groups p4(1)2(1)2 or p4(3)2(1)2 with the cell parameters a = b = 98.6 and c = 62.7 a. estimation of the crystal density and consideration of the possible values for v(m) indicate that there is either a dimer or trimer in the asymmetric unit. ...	1997	15299955
creation of libraries with long orfs by polymerization of a microgene.	we describe a novel method for constructing pools of dna sequences that encode large proteins with molecular diversity. sets of primer pairs that form 8 to 10 complementary base pairs in the 3' region and have double mismatch pairs at their 3'-oh ends were designed so that primer dimers recreated short stretches of dna (microgenes) devoid of termination codons. cycles of denaturation and elongation reactions with a pair of primers, four dntps, and 3'-5' exo+ thermostable dna polymerase gave head ...	1997	9108059
counterselectable markers: untapped tools for bacterial genetics and pathogenesis.		1998	9712740
molecular and biotechnological aspects of microbial proteases.	proteases represent the class of enzymes which occupy a pivotal position with respect to their physiological roles as well as their commercial applications. they perform both degradative and synthetic functions. since they are physiologically necessary for living organisms, proteases occur ubiquitously in a wide diversity of sources such as plants, animals, and microorganisms. microbes are an attractive source of proteases owing to the limited space required for their cultivation and their ready ...	1998	9729602
major facilitator superfamily.	the major facilitator superfamily (mfs) is one of the two largest families of membrane transporters found on earth. it is present ubiquitously in bacteria, archaea, and eukarya and includes members that can function by solute uniport, solute/cation symport, solute/cation antiport and/or solute/solute antiport with inwardly and/or outwardly directed polarity. all homologous mfs protein sequences in the public databases as of january 1997 were identified on the basis of sequence similarity and sho ...	1998	9529885
enterocins l50a and l50b, two novel bacteriocins from enterococcus faecium l50, are related to staphylococcal hemolysins.	enterocin l50 (entl50), initially referred to as pediocin l50 (l. m. cintas, j. m. rodríguez, m. f. fernández, k. sletten, i. f. nes, p. e. hernández, and h. holo, appl. environ. microbiol. 61:2643-2648, 1995), is a plasmid-encoded broad-spectrum bacteriocin produced by enterococcus faecium l50. it has previously been purified from the culture supernatant and partly sequenced by edman degradation. in the present work, the nucleotide sequence of the entl50 locus was determined, and several putati ...	1998	9555877
structural and biochemical analysis of the sheath of phormidium uncinatum.	the sheath of the filamentous, gliding cyanobacterium phormidium uncinatum was studied by using light and electron microscopy. in thin sections and freeze fractures the sheath was found to be composed of helically arranged carbohydrate fibrils, 4 to 7 nm in diameter, which showed a substantial degree of crystallinity. as in all other examined motile cyanobacteria, the arrangement of the sheath fibrils correlates with the motion of the filaments during gliding motility; i.e., the fibrils formed a ...	1998	9683490