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extracellular fibrils and contact-mediated cell interactions in myxococcus xanthus.contact-mediated cell-cell interactions play an important role in the social life-style of myxococcus xanthus. previous investigations have demonstrated that fimbriae (also referred to as pili) and extracellular fibrils are involved in these social interactions (l. j. shimkets, microbiol. rev. 54:473-501, 1990). we have used the relatively new technique of low-voltage scanning electron microscopy (an ultra-high-resolution scanning technique that allows for the nanometer resolution of biological ...19911744036
release of a cell surface protein during development of myxococcus xanthus.vgp is a major cell-surface glycoprotein present in vegetative cells of myxococcus xanthus. serological assays indicated that this protein was released from cells and accumulated in the medium during development, i.e., aggregation, fruiting body formation, and myxosporulation. cells induced to form spores in the absence of aggregation retained vgp, indicating that loss of vgp was associated with developmental aggregation rather than myxosporulation. anti-vgp antibodies inhibited vegetative cell ...19911744056
sensory transduction in the gliding bacterium myxococcus xanthus.sensory transduction in the gliding bacterium myxococcus xanthus is mediated by the frz genes. these genes are homologous to the chemotaxis genes of enteric bacteria and control the rate of cell reversal during gliding. sensory transduction is hypothesized to involve the recognition of substances present in the medium at the cell surface and the subsequent stimulation of a cytoplasmic methyl-accepting protein, frzcd. phosphorylation of frze is also involved in the sensory transduction pathway. d ...19911791749
a gene encoding a protein serine/threonine kinase is required for normal development of m. xanthus, a gram-negative bacterium.pcr reactions were carried out on the genomic dna of m. xanthus, a soil bacterium capable of differentiation to form fruiting bodies, using oligonucleotides representing highly conserved regions of eukaryotic protein serine/threonine kinases. a gene (pkn1) thus cloned contains an orf of 693 amino acid residues whose amino-terminal domain shows significant sequence similarity with the catalytic domain of eukaryotic protein serine/threonine kinases. the pkn1 gene was overexpressed in e. coli, and ...19911835671
sequence of hrdb, an essential gene encoding sigma-like transcription factor of streptomyces coelicolor a3(2): homology to principal sigma factors.the complete nucleotide sequence of the hrdb gene, an essential gene of streptomyces coelicolor a3(2), indicates the presence of an open reading frame encoding a putative polypeptide of 442 amino acid (aa) residues with an mr of 48,412. the principal sigma-like transcriptional factor of s. coelicolor (hrdb) protein showed an extensive aa sequence homology with the known principal sigma factors of escherichia coli, bacillus subtilis, pseudomonas aeruginosa and myxococcus xanthus. the degree of se ...19911840545
cell-cell interactions that direct fruiting body development in myxococcus xanthus.the soil bacterium, myxococcus xanthus initiates a developmental program when nutrients are limited. this results in the formation of a multicellular fruiting body structure filled with differentiated, environmentally resistant spores. at least four cell-cell signals, cell motility, and aggregation functions are required for the completion of fruiting body formation.19911840894
c-factor has distinct aggregation and sporulation thresholds during myxococcus development.c-factor, the protein product of the csga gene, acts as a short-range morphogenetic signal. it is required for fruiting body development of the gram-negative bacterium myxococcus xanthus. aggregation, sporulation, and expression of a set of genes that are c-factor dependent, all of which fail in csga mutant cells, are completely restored by addition of purified c-factor. we report here that, depending on its concentration, c-factor can elicit two distinct morphogenetic and transcriptional respon ...19911847908
physical map of the myxococcus xanthus chromosome.the genome of myxococcus xanthus, which is 9,454 kbp, is one of the largest bacterial genomes. the organization of the dna and the distribution of genes encoding social and developmental behaviors were examined by using pulsed field gel electrophoresis. intact genomic dna was digested with asei into 16 restriction fragments, which were separated by contour-clamped homogeneous electric field electrophoresis, purified, and radiolabeled. each asei fragment was hybridized to spei-digested dna and to ...19911848221
transcription of the myxobacterial hemagglutinin gene is mediated by a sigma 54-like promoter and a cis-acting upstream regulatory region of dna.myxobacterial hemagglutinin (mbha) is a major developmentally induced protein that accumulates during the period of cellular aggregation of the fruiting bacterium myxococcus xanthus. in this study, dna sequences mediating the transcriptional regulation of mbha have been identified. examination of nucleotide sequences upstream of the start site for mbha transcription has indicated a region of dna that bears strong homology to the consensus sequence for promoters recognized by the sigma 54 holoenz ...19911850403
a unique repetitive dna sequence in the myxococcus xanthus genome.we found a novel type of repetitive dna sequence in the myxococcus xanthus genome. the first repetitive sequence is located in the spacer region between the ops and tps genes. we cloned five other repetitive sequences using the first repetitive sequence as a probe and determined their nucleotide sequences. comparison of these sequences revealed that the repetitive sequences consist of a 87-bp core sequence and that some clones share additional homology on their flanking regions.19911900509
myxococcus xanthus protein c is a major spore surface protein.fruiting body formation in myxococcus xanthus involves the aggregation of cells to form mounds and the differentiation of rod-shaped cells into spherical myxospores. the surface of the myxospore is composed of several sodium dodecyl sulfate (sds)-soluble proteins, the best characterized of which is protein s (mr, 19,000). we have identified a new major spore surface protein called protein c (mr, 30,000). protein c is not present in extracts of vegetative cells but appears in extracts of developi ...19911900510
low-temperature induction of myxococcus xanthus developmental gene expression in wild-type and csga suppressor cells.the csga gene encodes an extracellular protein that plays an essential role in the regulation of fruiting-body formation and sporulation of myxococcus xanthus. the csga suppressor allele soc-500 (formerly referred to as csp-500) was selected based on its ability to restore sporulation to csga cells under developmental conditions at 32 degrees c. the soc-500 allele was subsequently found to induce sporulation of csga+ or csga cells simply by shifting the temperature of vegetatively growing cells ...19911901052
development in myxococcus xanthus involves differentiation into two cell types, peripheral rods and spores.myxococcus xanthus, a gram-negative bacterium, has a complex life cycle. in response to starvation, most cells in a population participate in the formation of multicellular aggregates (i.e., fruiting bodies) in which cells differentiate into spores. however, some cells do not enter aggregates. in this and the two accompanying reports, the biology and physiology of these nonaggregated cells is examined. a technique to separate aggregated cells from nonaggregated cells was developed; then differen ...19911904430
analysis of myxococcus xanthus cell types by two-dimensional polyacrylamide gel electrophoresis.myxococcus xanthus is a gram-negative, soil-dwelling bacterium that undergoes development in response to depletion of nutrients. whereas most cells aggregate into multicellular mounds in which they differentiate into spores, 10 to 20% of the developing cells remain outside fruiting bodies as peripheral rods. we used two-dimensional polyacrylamide gel electrophoresis to analyze the global expression of polypeptides in cells taken from six stages in the life cycle: vegetatively growing cells, cell ...19911904431
behavior of peripheral rods and their role in the life cycle of myxococcus xanthus.myxococcus xanthus is a gram-negative bacterium with a complex life cycle including a developmental phase in which cells aggregate and sporulate in response to starvation. in previous papers, we have described a heretofore unsuspected layer of complexity in the development of m. xanthus: vegetatively growing cells differentiate into two cell types during development. in addition to the differentiation of spores within fruiting bodies, a second cell type, peripheral rods, arises outside fruiting ...19911904432
protein u, a late-developmental spore coat protein of myxococcus xanthus, is a secretory protein.protein u is a spore coat protein produced at the late stage of development of myxococcus xanthus. this protein was isolated from developmental cells, and its amino-terminal sequence was determined. on the basis of this sequence, the gene for protein u (pru) was cloned and its dna sequence was determined, revealing an open reading frame of 179 codons. the product from this open reading frame has a typical signal peptide of 25 amino acid residues at the amino terminal end, followed by protein u o ...19911904442
deoxyribonuclease activities in myxococcus coralloides d.myxococcus coralloides d produced cell-bound deoxyribonucleases (dnases) during the exponential phase of growth in liquid medium. dnase activity was much higher than that detected in other myxobacterial strains and was fractionated into three different peaks by filtration through sephadex g-200. the dnases were named g, m and p. the optimum temperatures were 37 degrees c, 33 degrees c and 25 degrees c respectively, although high activities were recorded over the temperature range 20-45 degrees c ...19911917725
targeted disruption of the myxococcus xanthus orotidine 5'-monophosphate decarboxylase gene: effects on growth and fruiting-body development.the myxococcus xanthus gene coding for orotidine 5'-monophosphate (omp) decarboxylase (ec 4.1.1.23) was cloned. the m. xanthus uraa gene efficiently complemented an escherichia coli omp decarboxylase mutant, permitting it to grow in the absence of uracil. electroporation of m. xanthus with a circular plasmid carrying a selectable uraa::kan gene disruption resulted in homologous recombination at the chromosomal uraa locus. chromosomal integration of the gene disruption plasmid created heterozygou ...19911938885
effects of glucosamine on lysis, glycerol formation, and sporulation in myxococcus xanthus.glucosamine (glcn), which has previously been shown to rescue fruiting body formation, lysis, and sporulation in a developmental mutant (g. janssen and m. dworkin, dev. biol. 112:194-202, 1985), induced lysis in vegetative and developing wild-type cells and inhibited fruiting body formation. it also resulted in a transient, intracellular increase in the concentration of glycerol, a known sporulation inducer, and sporulation of the surviving cells. phospholipase activity, which was shown to be no ...19911938915
bacillus subtilis chen, a homolog of chea, the central regulator of chemotaxis in escherichia coli.the bacillus subtilis chen gene was isolated, sequenced, and expressed. it encodes a large negatively charged protein with a molecular weight of approximately 74,000. the predicted protein sequence has 33 to 34% identity with the escherichia coli and salmonella typhimurium chea and myxococcus xanthus frze sequences. these proteins are found to autophosphorylate and are members of the same histidine kinase signal modulating family. chen has several conserved regions (including the histidine that ...19911938941
function of mgla, a 22-kilodalton protein essential for gliding in myxococcus xanthus.single mutations in the mgla gene in myxococcus xanthus render cells incapable of gliding. the mgla strains are unique in that all other nonmotile strains of m. xanthus isolated are the result of at least two independent mutations in separate motility system genes. translational fusions of trpe, or of lacz, to mgla were constructed, and the resulting fusion polypeptides were used to generate antibodies. antibodies specific to mgla protein were purified. antibody-tagged mgla was found localized t ...19911938957
upstream gene of the mgl operon controls the level of mgla protein in myxococcus xanthus.the mgl operon contains two open reading frames (orfs) which are transcribed together. a collection of nonmotile mutants helped to define the downstream orf as the mgla gene. single mutations at the mgla locus completely abolish motility. a series of deletion mutations was constructed to determine the role of the upstream orf (now called mglb). a strain carrying a deletion in mglb and with an intact mgla produces small colonies. the cells are motile, but their rate of swarm spreading is reduced. ...19911938958
the amino acid sequence of nucleoside diphosphate kinase i from spinach leaves, as deduced from the cdna sequence.the primary structure of nucleoside diphosphate (ndp) kinase from spinach leaves has been deduced from its cdna sequence. a lambda gt 11 cdna library derived from spinach leaves was screened using an antibody against ndp kinase i, which we previously purified to electrophoretic homogeneity (t. nomura, t. fukui, and a. ichikawa, 1991, biochim. biophys. acta 1077, 47-55). the cdna sequences of positive clones contained the amino acid coding region (444 base pairs) for ndp kinase i as well as 5' an ...19921322113
mutation and mapping of genes involved in production of the antibiotic ta in myxococcus xanthus.transposition of tnv and tn5lac into myxococcus xanthus yielded 8,381 kanamycin-resistant mutants that were tested for antibiotic ta production. twenty-four of the mutants were nonproducers of ta (less than 0.4 ng/ml), and 3 produced a higher level (2.5 micrograms/ml) than the parent strain (1.5 micrograms/ml). for most of the strains, there was 100% cotransduction between kanamycin resistance and the altered ta phenotype. southern blot analysis of restriction digests of the mutant dna indicated ...19921332595
effect of mechanical removal of pili on gliding motility of myxococcus xanthus.gliding motility of myxococcus xanthus is governed by both the adventurous (a) and the social (s) motility gene systems. the presence of pili has previously been shown to be correlated with a genetically intact s-motility system (d. kaiser, proc. natl. acad. sci. usa 76:5952-5956, 1979). the purpose of the present work was to study the direct effect of mechanical removal of pill on the social motility of m. xanthus. depiliation resulted in (i) a loss of streaming motility of a- s+ mutants, i.e., ...19921353759
characterization of the complex pdxh-tyrs operon of escherichia coli k-12 and pleiotropic phenotypes caused by pdxh insertion mutations.we report the first molecular genetic analysis of a pyridoxine 5'-phosphate oxidase, the pdxh gene product of escherichia coli k-12. chromosomal insertions in and around pdxh were generated with various transposons, and the resulting phenotypes were characterized. the dna sequence of pdxh was determined, and the promoters of pdxh and the downstream gene tyrs, which encodes tyrosyl-trna synthetase, were mapped by rnase t2 protection assays of chromosomal transcripts. these combined approaches led ...19921356963
csga expression entrains myxococcus xanthus development.the development cycle of the myxobacterium myxococcus xanthus consists of three partially overlapping morphological stages referred to as rippling, fruiting body formation, and sporulation, all of which are absent in csga null mutants. the csga gene product is an extracellular protein, referred to as the c signal, which is essential for developmental cell-cell interactions. csga expression increases throughout development, reaching its peak during sporulation. csga was made limiting for developm ...19921372277
similarity between the myxococcus xanthus and stigmatella aurantiaca reverse transcriptase genes associated with multicopy, single-stranded dna.to determine the evolutional relationship of bacterial retroelements of myxococcus xanthus and stigmatella aurantiaca, the nucleotide sequence of 3,060 bases encompassing msr, msd, and the upstream region of msd (downstream of msr) of s. aurantiaca dw4 was determined and compared with the same region from m. xanthus. an open reading frame was found 92 bases upstream of msd which encoded a polypeptide of 480 amino acid residues having 73% identity with the reverse transcriptase of m. xanthus. tog ...19921372604
in vivo production of a stable single-stranded cdna in saccharomyces cerevisiae by means of a bacterial retron.gram-negative bacteria such as myxococcus xanthus, stigmatella aurantiaca, and escherichia coli contain retroelements called retrons. retrons consist of the msr-msd region and the gene for reverse transcriptase (rt), which are essential for the production of the branched rna-linked ms-dna (multicopy single-stranded dna). in this study, we attempted to produce msdna in the yeast saccharomyces cerevisiae. retron ec67 from e. coli, which is responsible for the production of msdna-ec67, was cloned u ...19921378616
a-signalling and the cell density requirement for myxococcus xanthus development.mutations in any of three asg (a-signalling) loci cause fruiting body development of myxococcus xanthus to arrest at about the 2-h stage. development can be restored to asg mutants by the addition of conditioned buffer in which wild-type cells have been developing or of a-factor purified from the conditioned buffer. two forms of a-factor have been identified: heat-stable a-factor, which is composed of amino acids and peptides, and heat-labile a-factor, which consists of at least two proteases. a ...19921429458
control of cell density and pattern by intercellular signaling in myxococcus development.myxococcus xanthus cells feed, move, and develop cooperatively. genetic, biochemical, and cell mosaic studies demonstrate that cells coordinate their multicellular behavior by transmission of intercellular signals. starvation for amino acids at sufficiently high density on a solid surface initiates a series of events culminating in the formation of a multicellular structure called a fruiting body filled with dormant, environmentally resistant spores. this review discusses how myxobacteria use ex ...19921444251
use of tn5lac to study expression of genes required for production of the antibiotic ta.the beta-galactosidase activities arising from tn5lac insertions in several genes required for antibiotic ta production were measured under different growth conditions. in all of the non-ta-producing mutants, the beta-galactosidase specific activity was higher when the cells were grown in nutrient-limited 0.5cts medium (0.5% casitone plus alanine, serine, and glucose) than in rich 2ct medium (2% casitone). one of the mutants, 420, had low beta-galactosidase specific activity in both media. the o ...19921444312
sporulation in prokaryotes and lower eukaryotes.during the past year, highlights in sporulation research include the demonstration that phosphorylation of spooa is a critical factor in bacillus subtilis development; the identification of c alpha proteins, adenylyl cyclase and protein kinase a genes in dictyostelium; proof that an endogenous antisense rna regulates gene expression in dictyostelium; and characterization of a second type of differentiated cell in myxococcus.19921458028
determinants of an unusually stable mrna in the bacterium myxococcus xanthus.myxococcus xanthus is a gram-negative bacterium which has a complex life cycle that includes development (fruiting body formation). the gene for myxobacterial haemagglutinin, mbha, is developmentally regulated and highly expressed. in this report we show that the mbha mrna is exceptionally stable for a prokaryotic organism, exhibiting a chemical half life (t1/2) of 150 min at 18 h of development. the mbha mrna was not stable in vegetatively growing cells nor was it stable when expressed in esche ...19921479889
a new bioactive molecule for improving vascular graft patency: exploratory trials in dogs.myxalin is a new bioactive molecule that we have isolated from the culture medium of myxococcus xanthus, a non-pathogenic gram negative bacterium. this glycopeptide possesses an antithrombotic effect in vivo and has been shown to promote human endothelial cell growth in vitro. with the object of exploring its ability to improve vascular graft healing and patency, myxalin was immobilized on 6 mm diameter knitted polyester prostheses using gelatin as a carrier, and the prosthesis was then implante ...19921516289
cell surface modifications induced by calcium ion in the myxobacterium stigmatella aurantiaca.calcium ion induces in the myxobacterium stigmatella aurantiaca the ability to glide on solid surfaces and to become cohesive (d. f. gilmore and d. white, j. bacteriol. 161:113-117, 1985; b. j. womack, d. f. gilmore, and d. white, j. bacteriol. 171:6093-6096, 1989). the addition of calcium ion to the growth medium resulted in the formation of extracellular fibrils, the appearance in the membrane fractions of a 30-kda protein, and the accumulation in a low-speed centrifugal pellet of 10 polypepti ...19921522058
proteins that rescue a-signal-defective mutants of myxococcus xanthus.the asg mutants of myxococcus xanthus are defective in the production of an extracellular substance, called a-factor, that is required for expression of a set of fruiting body-specific genes. a-factor is released by wild-type cells (asg+) after 1 to 2 h of development. when a-factor is added to asg mutant cells, it restores expression of their a-factor-dependent genes. rescue of beta-galactosidase production in an asg mutant carrying the a-factor-dependent lacz transcriptional fusion (omega 4521 ...19921577696
identification of heat-stable a-factor from myxococcus xanthus.the asg mutants of myxococcus xanthus fail to produce a set of related substances called a-factor. a-factor is released into the medium and is required early in fruiting body development. lacking a-factor, the asg mutants are defective in aggregation, sporulation, and expression of most genes whose products appear later than 1 h after development is induced by starvation. previous work has shown that these defects are reversed when a-factor, released by developing wild-type cells, is added to as ...19921577697
on the evolution of the bacterial major sigma factors.the existence of internal sequence homologies between the n-terminal halves of the gram-negative bacterial major sigma factors and their c-terminal halves, which correspond to minor factors, is reported. in the case of escherichia-salmonella sigma-70, an apparent homology was even found between the c-terminal helix-turn-helix dna-binding motif and the corresponding region of the peptide n half, which, however, is not directly engaged in promoter recognition. it is proposed that major sigma facto ...19921602496
use of myxalin for improving vascular graft healing: evaluation of biocompatibility in rats.myxalin is a glycopeptide extracted recently from a gram-negative bacterium. it has blood anticoagulant properties and can enhance endothelial cell growth. with the ultimate objective of using this bioactive molecule to promote vascular graft healing, this study assessed its biocompatibility in vivo by comparing the cellular and immunological responses of gelatin-coated knitted polyester grafts with and without myxalin following implantation in the peritoneal cavity of rats for prescheduled peri ...19921610738
methylation of frzcd, a methyl-accepting taxis protein of myxococcus xanthus, is correlated with factors affecting cell behavior.myxococcus xanthus, a nonflagellated gliding bacterium, exhibits multicellular behavior during vegetative growth and fruiting body formation. the frizzy (frz) genes are required to control directed motility for these interactions. the frz genes encode proteins that are homologous to all of the major enteric chemotaxis proteins, with the exception of chez. in this study, we characterized frzcd, a protein which is homologous to the methyl-accepting chemotaxis proteins from the enteric bacteria. fr ...19921624419
production of an extracellular milk-clotting activity during development in myxococcus xanthus.we describe here an extracellular proteolytic activity secreted during both growth and submerged development by myxococcus xanthus dk1622. this activity yields the clotting of kappa-casein at ph 6 and is inhibited by specific inhibitors of aspartic proteases. secretion of this milk-clotting proteolytic activity (of mcp) is time regulated during the developmental cycle, with a large increase near 9 h poststarvation, but its production does not require cell-cell contact. the lack of secretion of t ...19921629171
identification of a putative eukaryotic-like protein kinase family in the developmental bacterium myxococcus xanthus.myxococcus xanthus is a gram-negative bacterium which, upon starvation, undergoes a spectacular developmental cycle culminating in the formation of spore-filled fruiting bodies. we recently characterized a protein serine-threonine kinase (pkn1) that is required for normal development (j. munoz-dorado, s. inouye, and m. inouye, cell 67:995-1006, 1991). pkn1 was cloned by polymerase chain reaction amplification with primers designed from conserved sequences in eukaryotic protein kinases. in this s ...19921644772
the orotidine-5'-monophosphate decarboxylase gene of myxococcus xanthus. comparison to the omp decarboxylase gene family.the nucleotide sequence of the myxococcus xanthus orotidine-5'-monophosphate decarboxylase (omp dcase) gene was determined. the derived protein sequence is not closely related to other prokaryotic omp dcase sequences; nor is it closely related to any eukaryotic omp dcase sequences. progressive multiple alignment of the m. xanthus omp dcase protein sequence with 19 other omp dcase sequences revealed four conserved regions present in all 20 sequences. ten entirely conserved residues were found in ...19921730672
a gene encoding a protein related to eukaryotic protein kinases from the filamentous heterocystous cyanobacterium anabaena pcc 7120.protein kinases play essential roles in the development of eukaryotic cells. these enzymes display various degrees of sequence similarity in their catalytic domains. this conservation has allowed the identification of protein kinases in a variety of organisms, including the gram-negative bacterium myxococcus xanthus. in this study, sequences related to those encoding eukaryotic protein kinases were amplified by pcr from dna of anabaena pcc 7120, a filamentous cyanobacterium that differentiates c ...19937505448
devrs, an autoregulated and essential genetic locus for fruiting body development in myxococcus xanthus.two tn5 lac insertions into the myxococcus genome at sites omega 4414 and omega 4473, which are separated by 550 nucleotides, inactivate fruiting body development. sporulation is decreased 100- to 10,000-fold. at least two genes, devr and devs, are transcribed in this region, probably as an operon. expression of devr begins by 6 h after starvation has initiated development. on the basis of their nucleotide sequences, devr and devs are expected to encode proteins of 302 and 214 amino acids, respe ...19937693658
clustering and co-ordinated activation of carotenoid genes in myxococcus xanthus by blue light.blue light activates carotenoid production in the non-photosynthetic, gram-negative bacterium myxococcus xanthus. light is known to stimulate the expression of two unlinked genes for carotenoid synthesis, carb and carc, through a mechanism in which the regulatory genes cara, carq and carr take part. genes carq and carr are linked together at a separate locus, whereas cara is linked to carb. we have introduced tn5 at various sites between cara and carb. chemical analyses of the mutant strains dem ...19937968516
light-induced carotenogenesis in myxococcus xanthus: dna sequence analysis of the carr region.the carr region encodes a light-inducible promoter, a negative regulator of the promoter and a trans-acting activator that controls the light-inducible myxococcus xanthus carotenoid biosynthesis regulon. dna sequence analysis revealed, downstream of the promoter, three translationally coupled genes, carq, carr and cars. sequencing of mutations demonstrated that carr encoded the negative regulator and was an integral membrane protein. mutant construction and sequencing revealed that cars was the ...19937934835
a physical and genetic map of the stigmatella aurantiaca dw4/3.1 chromosome.a physical map of the myxobacterium stigmatella aurantiaca dw4/3.1 chromosome was constructed by pulsed-field gel (pfg) long-range mapping. one-and two-dimensional pulsed-field gel analyses were used together with reciprocal double-restriction, cross-hybridization and hybridization fingerprint analysis. these pfg results were confirmed by smith-birnstiel analysis, by southern hybridization using linking clones and clones of a lambda genomic library for the determination of adjacent restriction f ...19937934859
the uraa locus and homologous recombination in mycobacterium bovis bcg.molecular genetic manipulation of mycobacteria would benefit from the isolation of mycobacterial genes that could serve both as genetic markers and as sequences used to target homologous integration of recombinant dna into the genome. we isolated the mycobacterium bovis bcg gene encoding orotidine-5'-monophosphate decarboxylase (omp-dcase) by complementing an escherichia coli mutant defective in this activity. the bcg omp-dcase gene (uraa) and the flanking dna were sequenced. the predicted bcg o ...19938226675
fatal attraction. 19938247147
identification of esg, a genetic locus involved in cell-cell signaling during myxococcus xanthus development.jd258, a tn5 insertion mutant of myxococcus xanthus, was shown to have major defects in three development-associated properties: expression of the developmentally regulated tps gene, spore formation, and production of multicellular fruiting bodies. the defects in tps gene expression and sporulation could be substantially corrected, at the phenotypic level, by mixing jd258 with wild-type cells (extracellular complementation). by this criterion, jd258 appeared to be a new member of a group of cond ...19938253664
crystal structure of myxococcus xanthus nucleoside diphosphate kinase and its interaction with a nucleotide substrate at 2.0 a resolution.the x-ray crystallographic structure of nucleoside diphosphate (ndp) kinase from myxococcus xanthus has been determined using multiple isomorphous replacement techniques and refined at 2.0 a resolution to a crystallographic r-factor of 0.17. this is the first report of the structure of an enzymatically active ndp kinase and of the enzyme with a bound nucleotide. the structure has been determined in p4(3)2(1)2 and i222 crystal forms. the enzyme monomer consists of a four-stranded antiparallel bet ...19938263923
mutations in two new loci that impair both extracellular protein production and development in myxococcus xanthus.two transposon insertion mutants of myxococcus xanthus altered in the secretion of protein as determined by the hydrolytic activities of several enzymes during vegetative growth were also unable to complete fruiting body formation and were severely impaired in sporulation. the insertions were located in the same part of the m. xanthus chromosome but were unlinked by transduction and therefore define two distinct loci, called exca and excb. since both exc +/- mutants were able to rescue developme ...19938320239
myxococcus xanthus encodes an atp-dependent protease which is required for developmental gene transcription and intercellular signaling.the bsga gene of myxococcus xanthus plays an essential role in the regulation of early gene expression during fruiting body formation and sporulation. bsga mutants behave as though unable to initiate a required cell-cell interaction and consequently fail to transcribe normal levels of many developmentally induced genes. we determined the nucleotide sequence of bsga, which predicts a single gene encoding a 90.4-kda protein. the deduced bsga protein shares 45 and 48% amino acid identity with the l ...19938331082
the lond gene is homologous to the lon gene encoding an atp-dependent protease and is essential for the development of myxococcus xanthus.myxococcus xanthus contains two genes (lonv and lond) homologous to the escherichia coli lon gene for an atp-dependent protease. we found that the lond gene encodes a 90-kda protein consisting of 827 amino acid residues. the lond gene product shows 49, 48, and 52% sequence identity to the products of the m. xanthus lonv, e. coli lon, and bacillus brevis lon genes, respectively. when a lond-lacz fusion was used, lond was expressed during both vegetative growth and development. however, while lond ...19938331083
oar, a 115-kilodalton membrane protein required for development of myxococcus xanthus.myxococcus xanthus is a developmental gram-negative bacterium which forms multicellular fruiting bodies upon nutrient starvation. this bacterium was found to contain a 115-kda membrane protein which separated with the inner membrane fraction by sucrose density gradient centrifugation. the gene for this protein was cloned, and its dna sequence was determined. the deduced amino acid sequence consists of 1,061 residues. this protein contains a putative signal sequence and many short segments, found ...19938335633
frzcd, a methyl-accepting taxis protein from myxococcus xanthus, shows modulated methylation during fruiting body formation.the frizzy (frz) genes of myxococcus xanthus are required to control directed motility during vegetative growth and fruiting body formation. frzcd, a protein homologous to the methyl-accepting chemotaxis proteins from enteric bacteria, is modified by methylation in response to environmental conditions. transfer of cells from rich medium to fruiting medium initially caused rapid demethylation of frzcd. subsequently, the amount of frzcd increased, but most remained unmethylated. at about the time ...19938335650
spatial restriction of cellular differentiation.myxococcus xanthus cells differentiate into myxospores within a fruiting body, an aggregate of approximately 10(5) cells. previous work had discerned an inner and outer domain within the fruiting body differentiated by cell density and cell alignment. to test whether the two domains might play different roles in spore differentiation, developmentally regulated gene fusions were screened for expression restricted to one domain or the other. transcriptional lacz fusions to 80 developmentally regul ...19938370517
autophosphorylation of nucleoside diphosphate kinase from myxococcus xanthus.the nucleoside diphosphate kinase (ndp kinase) from myxococcus xanthus has been purified to homogeneity and crystallized (j. munoz-dorado, m. inouye, and s. inouye, j. biol. chem. 265:2702-2706, 1990). in the presence of atp, the ndp kinase was autophosphorylated. phosphoamino acid analysis was carried out after acid and base hydrolyses of phosphorylated ndp kinase. it was found that the protein was phosphorylated not only at a histidine residue but also at a serine residue. replacement of histi ...19938381783
light-induced carotenogenesis in myxococcus xanthus: genetic analysis of the carr region.carotenogenesis is light-inducible in the non-photosynthetic, gram-negative, bacterium myxococcus xanthus. we report the characterization of the carr region which controls this phenomenon. insertion of transposon tn5 close to the carr region caused a dominant, carotenoid-constitutive mutation because of the presence of a constitutive, outward-reading promoter in the is50l component of tn5. in wild-type cells, a powerful, tightly-regulated, light-inducible promoter directs the transcription of tw ...19938384685
the mgla component of the binding protein-dependent galactose transport system of salmonella typhimurium is a galactose-stimulated atpase.binding protein-dependent transport systems mediate the accumulation of several ions, sugars, amino acids, and peptides in gram-negative bacteria by using the energy of atp hydrolysis and belong to a superfamily of membrane proteins which extends to eukaryotic cells and includes the multidrug resistance p-glycoprotein and the cystic fibrosis transmembrane conductance regulator. the binding protein-dependent galactose transport system of salmonella typhimurium comprises four proteins which have b ...19938387496
beta-galactosidase activity in single differentiating bacterial cells.myxococcus xanthus strains containing transcriptional fusions to lacz were analyzed and fractionated by differences in their levels of beta-galactosidase expression. the fluorogenic substrate for beta-galactosidase, fluorescein di-beta-galactopyranoside, was introduced into m. xanthus cells during a rapid decrease in osmolarity of the medium followed by a return to isoosmolarity. fluorescein, the product of hydrolysis, was retained within the cells and their viability was preserved. fluorescence ...19938396263
isoprenoid biosynthesis in bacteria: two different pathways?the biosynthesis of isopentenylpyrophosphate, a central intermediate of isoprenoid formation, was investigated in six different bacterial organisms. cell-free extracts of myxococcus fulvus, staphylococcus carnosus, lactobacillus plantarum and halobacterium cutirubrum converted [14c]acetyl-coa or [14c]hydroxymethylglutaryl-coa to [14c]mevalonic acid. furthermore, [14c]mevalonic acid, [14c]mevalonate-5-phosphate and [14c]mevalonate-5-pyrophosphate were metabolized to [14c]isopentenylpyrophosphate. ...19938405922
chemotaxis plays a role in the social behaviour of myxococcus xanthus.myxococcus xanthus is a gram-negative bacterium that glides on a solid surface and displays a wide range of social behaviour including microbial development. the frz genes are homologues to the chemotaxis genes of escherichia coli and salmonella typhimurium and have been shown to be involved in microbial development. however, chemotaxis has never been clearly demonstrated in myxococcus. in this study, we showed that m. xanthus exhibited tactic movements to many chemicals when they were subjected ...19938412706
eukaryotic-like protein serine/threonine kinases in myxococcus xanthus, a developmental bacterium exhibiting social behavior.myxococcus xanthus, a gram-negative bacterium exhibits a spectacular life cycle and social behavior. its developmental cycle and multicellular morphogenesis resemble those of eukaryotic slime molds such as dictyostelium discoideum. on the basis of this resemblance, we explored the existence of eukaryotic-like protein serine/threonine kinases which are known to play important roles in signal transduction during development of d. discoideum. it was indeed found that m. xanthus contains a large fam ...19938432741
growth phase dependence of the activation of a bacterial gene for carotenoid synthesis by blue light.myxococcus xanthus responds to blue light by producing carotenoid pigments. a mutation at a gene named carc is known to block the metabolism of phytoene, a carotenoid precursor, and this gene has now been cloned and sequenced. we show here that gene carc, which is homologous to phytoene dehydrogenase genes from other organisms, is tightly regulated by light through a mechanism that operates only when the cells have reached the stationary phase or are starved of a carbon source. a genetic element ...19938467787
cloning and nucleotide sequence of the myxococcus xanthus lon gene: indispensability of lon for vegetative growth.the lon gene of escherichia coli is known to encode protease la, an atp-dependent protease associated with cellular protein degradation. a lon gene homolog from myxococcus xanthus, a soil bacterium which differentiates to form fruiting bodies upon nutrient starvation, was cloned and characterized by use of the lon gene of e. coli as a probe. the nucleotide sequence of the m. xanthus lon gene was determined. it contains an open reading frame that encodes a 92-kda protein consisting of 817 amino a ...19938468287
antifungal activity of myxococcus species 1 production, physicochemical and biological properties of antibiotics from myxococcus fulvus s110 (myxobacterales).chloroform extracts of the culture supernatant of a strain of myxococcus fulvus isolated from soil were fungistatic and prevented germination of spores of botrytis cinerea. the antibiotics were produced during the exponential phase of growth and the effects of altering medium composition are described. the activity was fractionated into neutral, acidic and basic fractions. the neutral fraction had a molecular weight of 244 and was tentatively identified as 11-phenyl-undecadiene-2-ol. the acidic ...19938469176
the two motility systems of myxococcus xanthus show different selective advantages on various surfaces.myxococcus xanthus, a bacterium that forms fruiting bodies, moves by gliding motility utilizing dual motility systems that differ both genetically and morphologically [system a, having at least 21 genetic loci and moving mainly single cells, and system s, having at least 10 genetic loci and moving groups (rafts) of cells] [hodgkin, j. & kaiser, d. (1979) mol. gen. genet. 172, 177-191]. in this study, we found that a- and s-gliding-motility systems have different selective advantages on surfaces ...19938475084
two cell-density domains within the myxococcus xanthus fruiting body.myxococcus xanthus, one of the simplest of multicellular organisms, develops into an organized, multicellular aggregate, called a fruiting body. examination of the internal structure of the nascent fruiting body showed it to consist of a hemispherical outer domain of densely packed and ordered cells. inside this dense shell is an inner domain of less ordered cells at 3-fold lower cell density. single cells move in a bidirectional stream in the outer domain, orbiting the fruiting body throughout ...19938475116
how and why bacteria talk to each other. 19938500179
a new putative sigma factor of myxococcus xanthus.a third putative sigma factor gene, sigc, has been isolated from myxococcus xanthus by using the siga gene (formerly rpod of m. xanthus) as a probe. the nucleotide sequence of sigc has been determined, and an open reading frame of 295 residues (m(r) = 33,430) has been identified. the deduced amino acid sequence of sigc exhibits the features which are characteristic of other bacterial sigma factors. the characterization of a sigc-lacz strain has demonstrated that sigc expression is induced immedi ...19938501037
regulation of cohesion-dependent cell interactions in myxococcus xanthus.myxococcus xanthus has two nearly independent genetic systems, a and s, which appear to mediate adventurous (single-cell) movement and social (group) movement, respectively. in addition to a notable reduction in group movement, social motility mutants exhibit decreased biofilm formation, cell cohesion, dye binding, fibril production, and fruiting body formation. the stk-1907 allele, containing transposon tn5 insertion omega dk1907, was introduced into wild-type cells and many social motility mut ...19938501067
effect of dsp mutations on the cell-to-cell transmission of csga in myxococcus xanthus.the dsp locus contains genes involved in the subunit synthesis and/or assembly of fibrils that radiate outward from the myxococcus xanthus cell surface and attach to other cells. the csga gene encodes an extracellular protein morphogen which is essential for fruiting body development. the question of whether fibrils are involved in the transmission of csga to adjacent cells was investigated in three ways. first, the dsp and csga mutants were mixed in a ratio of 1:1 and allowed to develop; fruiti ...19938501068
rhizopodin, a new compound from myxococcus stipitatus (myxobacteria) causes formation of rhizopodia-like structures in animal cell cultures. production, isolation, physico-chemical and biological properties.a new cytostatic compound, rhizopodin, was isolated from the culture broth of the myxobacterium, myxococcus stipitatus. the compound inhibited growth of various animal cell cultures without killing the cells. the id50, measured by an mtt assay, was 12 approximately 30 ng/ml, depending on the cell line. especially cells growing fibroblast-like showed typical morphological changes. they became larger and within hour formed long branching and reticular runners. these morphological changes were irre ...19938514628
pim1 encodes a mitochondrial atp-dependent protease that is required for mitochondrial function in the yeast saccharomyces cerevisiae.the pim1 nuclear gene in the yeast saccharomyces cerevisiae encodes a mitochondrial atp-dependent protease that exhibits over 30% identity with atp-dependent protease la from escherichia coli, lon from bacillus brevis, and one from myxococcus xanthus. in addition, pim1 is 1133 amino acids long and has a putative mitochondrial import signal in the n-terminal region. enzymatic comparisons of normal pim1+ and deficient pim1-delta strains revealed that the atp-dependent protease is located within th ...19948276800
isolation and phenotypic characterization of myxococcus xanthus mutants which are defective in sensing negative stimuli.myxococcus xanthus is a gram-negative gliding bacterium that exhibits a complex life cycle. exposure of m. xanthus to chemicals like dimethyl sulfoxide (dmso) at nondeleterious concentrations or the depletion of nutrients caused several negative responses by the cells. dmso (> 0.1 m) or nutrient depletion triggered a repellent response: cell swarming was inhibited and frzcd (a methyl-accepting chemotaxis protein) was demethylated; higher concentrations of dmso (> 0.3 m) or prolonged starvation i ...19948300525
characterization of a pseudomonas aeruginosa gene cluster involved in pilus biosynthesis and twitching motility: sequence similarity to the chemotaxis proteins of enterics and the gliding bacterium myxococcus xanthus.the type 4 pili of pseudomonas aeruginosa are important cell-associated virulence factors that play a crucial role in mediating (i) bacterial adherence to, and colonization of, mucosal surfaces, (ii) a novel mode of flagella-independent surface translocation known as 'twitching motility', and (iii) the initial stages of the infection process for a number of bacteriophages. a new set of loci involved in pilus biogenesis and twitching motility was identified based on the ability of dna sequences d ...19947908398
autophosphorylation of nucleoside diphosphate kinase on non-histidine residues.recently, several reports appeared which described auto-phosphorylation of ndp kinase on residues different from the active-site histidine. based on these findings conclusions were drawn with respect to a regulation of enzyme activity and to a possible role as a metastasis suppressor. in this paper we show that although non-histidine autophosphorylation occurs on ndp kinases from mammals, lower eukaryotes and bacteria, less than 0.2% of the subunits are phosphorylated. using site-directed mutage ...19947926021
biochemical and structural analyses of the extracellular matrix fibrils of myxococcus xanthus.it is characteristic of myxobacteria to produce large amounts of extracellular material. this report demonstrates that this material in myxococcus xanthus is fibrillar and describes the structure and chemical composition of the fibrils. the extracellular matrix fibrils are the mediators of cell-cell cohesion in m. xanthus. as such, the fibrils play an important role in the cell-cell interactions that form the basis for the social and developmental lifestyle of this organism. the fibrils are comp ...19947929001
integral proteins of the extracellular matrix fibrils of myxococcus xanthus.the extracellular matrix fibrils of myxococcus xanthus are mediators of cell-cell cohesion and as such are required for the maintenance of the social lifestyle characteristic of these prokaryotes. the fibrils have also been implicated as factors involved in contact-mediated cell interactions and in signal exchange. the fibrils are extracellular carbohydrate structures with associated proteins. all of the major proteins associated with the fibrils react with monoclonal antibody 2105 and can be re ...19947929002
a physical map of the myxococcus xanthus chromosome.a physical map of the 9.2-mbp myxococcus xanthus dk1622 chromosome at a resolution of 25 kbp was constructed by using a strategy that is applicable to virtually all microorganisms. segments of the chromosome were used as hybridization probes to subdivide a yeast artificial chromosome (yac) library into groups of linked clones. the clones were aligned by comparing their ecori restriction patterns. the groups of yac clones ("contigs") were oriented and aligned with the genomic restriction map by m ...19947937810
elastolytic activity of map1, a protease from myxococcus xanthus.map1, a protease isolated from myxococcus xanthus, is demonstrated to be an elastase. although its elastolytic activity is lower than that of other well-known elastases, the size distribution of solubilized elastin peptides is similar. map1 as pancreatic elastase releases peptides with molecular weights higher than 10,000. however, the specificity of map1 is different since this enzyme cannot hydrolyze alanine oligomers as do pancreatic and pseudomonas aeruginosa elastases.19947951071
intercellular signalling. knowing that you're among friends.factors that are simultaneously secreted and sensed are used by cells to monitor local cell density; a recently discovered factor of this type controls the transformation-competence of bacillus subtilis.19947953564
a genetic link between light response and multicellular development in the bacterium myxococcus xanthus.the gram-negative bacterium myxococcus xanthus responds to blue light by producing carotenoid pigments (car+ phenotype). genes for carotenoid synthesis lie at two unlinked chromosomal sites, the carc and the carba operon, but are integrated in a single "light regulon" by the action of common trans-acting regulatory elements. three known regulatory genes are grouped together at the (light-inducible) carqrs operon. by screening the car phenotype of a large collection of transposon-induced mutants, ...19947958903
cloning, nucleotide sequence, and expression of the bacillus subtilis lon gene.the lon gene of escherichia coli encodes the atp-dependent serine protease la and belongs to the family of sigma 32-dependent heat shock genes. in this paper, we report the cloning and characterization of the lon gene from the gram-positive bacterium bacillus subtilis. the nucleotide sequence of the lon locus, which is localized upstream of the hemaxcdbl operon, was determined. the lon gene codes for an 87-kda protein consisting of 774 amino acid residues. a comparison of the deduced amino acid ...19947961402
isolated fibrils rescue cohesion and development in the dsp mutant of myxococcus xanthus.extracellular fibrils are involved in cell cohesion and cell development in myxococcus xanthus. one group of social motility mutants, dsp, is unable to produce extracellular fibrils; these mutants also lose the abilities to cohere and to develop. extracellular fibrils isolated from vegetative wild-type cells and added to dsp cells fully restored the abilities of these cells to cohere and to undergo normal morphological development. the fibrils thus mimic the ability of intact, wild-type cells to ...19947961490
refined x-ray structure of dictyostelium discoideum nucleoside diphosphate kinase at 1.8 a resolution.the x-ray structure of the nucleoside diphosphate kinase (ndp kinase) from dictyostelium discoideum has been refined at 1.8 a resolution from a hexagonal crystal form with a 17 kda monomer in its asymmetric unit. the atomic model was derived from the previously determined structure of a point mutant of the protein. it contains 150 amino acid residues out of 155, and 95 solvent molecules. the r-factor is 0.196 and the estimated accuracy of the average atomic position, 0.25 a. the dictyostelium st ...19947966307
increases in the intracellular concentration of glycerol during development in myxococcus xanthus.the role of glycerol as a natural morphogen of myxospore formation in myxococcus xanthus was examined. glycerol was extracted from cells undergoing development and analyzed by gas chromatography. glycerol is present in cells, and the intracellular level undergoes a series of transient increases during development. the data suggest a role for glycerol in myxosporulation and fruiting body morphogenesis, supporting the notion that this chemical induction of sporulation may represent a physiological ...19947988874
intercellular c-signaling and the traveling waves of myxococcus.early in their development into fruiting bodies, myxococcus xanthus cells organize themselves into dense bands that move as trains of traveling waves. c-factor, a 20-kd cell-surface bound protein, is a short-range developmental signal molecule required for these waves. what is the role of c-factor in the wave pattern? it is proposed that oriented collisions between cells initiate c-signaling, which, in turn, causes individual cells to reverse their direction of gliding. cells would move about on ...19947995518
molecular cloning and sequencing of an operon, carrs of azospirillum brasilense, that codes for a novel two-component regulatory system: demonstration of a positive regulatory role of carr for global control of carbohydrate catabolism.a pleiotropic carbohydrate mutant, cr17, of azospirillum brasilense rg (wild type) that assimilates c4 dicarboxylates (succinate and malate) but not carbohydrate (fructose, arabinose, galactose, glycerol, and gluconate) as c sources for growth was used to identify the car (carbohydrate regulation) locus by complementation analysis. the 2.8-kb genomic fragment that complemented the car- defect of cr17 and overlapped the fru operon (s. chattopadhyay, a. mukherjee, and s. ghosh, j. bacteriol. 175:3 ...19948002571
characterization of nucleoside-diphosphate kinase from pseudomonas aeruginosa: complex formation with succinyl-coa synthetase.the enzyme nucleoside-diphosphate kinase (ndk), responsible for the conversion of (deoxy)ribonucleoside diphosphates to their corresponding triphosphates, has been purified from pseudomonas aeruginosa. the n-terminal 12 amino acid sequence of p. aeruginosa ndk shows significant homology with that of myxococcus xanthus and that of escherichia coli. ndk enzyme activity is also associated with succinyl-coa synthetase activity in p. aeruginosa, whose alpha and beta subunits show extensive sequence h ...19948016083
protein purification, gene cloning and sequencing of an acidic endoprotease from myxococcus xanthus dk101.an acidic endoprotease (maep) secreted during vegetative growth by myxococcus xanthus dk101 was purified to homogeneity by a series of chromatographic procedures. the endoprotease cleaved the phe-met bond of kappa-casein under acidic conditions (ph 5.9). its apparent molecular mass and its isoelectric point have been estimated to be 12 kda and 4.5, respectively. from the n-terminal amino acid sequence, a set of two primers for polymerase chain reaction have been designed. amplification of the co ...19948020464
myxococcus xanthus c-factor, a morphogenetic paracrine signal, is similar to escherichia coli 3-oxoacyl-[acyl-carrier-protein] reductase and human 17 beta-hydroxysteroid dehydrogenase. 19948037687
analysis of the streptomyces coelicolor sige gene reveals the existence of a subfamily of eubacterial rna polymerase sigma factors involved in the regulation of extracytoplasmic functions.sigma e, an rna polymerase sigma factor of apparent m(r) 28,000, was previously identified by its ability to direct transcription from the p2 promoter of the agarose gene (daga) of streptomyces coelicolor. a degenerate oligonucleotide probe, designed from the n-terminal sequence of purified sigma e, was used to isolate the sigma e gene (sige). the predicted sequence of sigma e shows greatest similarity to sequences of seven other proteins: myxococcus xanthus carq, pseudomonas aeruginosa algu, ps ...19948052622
purification and characterization of an alkaline elastase from myxococcus xanthus.an extracellular elastase, termed myxococcus xanthus alkaline protease 1 (map1), has been purified from m. xanthus dk1622 culture supernatants by a combination of ion-exchange and affinity chromatographies. it consists of a single peptide chain of 39 kda. the elastolytic activity was totally suppressed by 10 mm 1,10-phenanthroline and the enzyme may then be classified as a metalloprotease. its ph optimum was estimated to be 8.2 with both elastin-orcein and succinyl-ala3 p-nitroanilide as substra ...19948055953
use of a phase variation-specific promoter of myxococcus xanthus in a strategy for isolating a phase-locked mutant.the bacterium myxococcus xanthus alternates between two colony types distinguished by colony morphology and pigmentation. because the two phases are interconvertible, this phenomenon has been termed phase variation. in one phase, the colonies are bright yellow, rough, and swarming. in the alternate phase, the colonies are tan and mucoid with smooth edges. during exponential vegetative growth, the populations within a colony reach an equilibrium of approximately 99% yellow and 1% tan cells. neith ...19948071210
increases in the intracellular concentration of glycerol during development in myxococcus xanthus s. courtney frasch.the role of glycerol as a natural morphogen of myxospore formation in myxococcus xanthus was examined. glycerol was extracted from cells undergoing development and analyzed by gas chromatography. glycerol is present in cells, and the intracellular level undergoes a series of transient increases during development. the data suggest a role for glycerol in myxosporulation and fruiting body morphogenesis supporting the notion that this chemical induction of sporulation may represent a physiological ...19948076811
nmr-derived three-dimensional solution structure of protein s complexed with calcium.protein s is a developmentally-regulated ca(2+)-binding protein of the soil bacterium myxococcus xanthus. it functions by forming protective, multilayer spore surface assemblies which may additionally act as a cell-cell adhesive. protein s is evolutionarily related to vertebrate lens beta gamma-crystallins.19948081742
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