Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Actinobacillus actinomycetemcomitans was found to express a polypeptide immunologically related to the Neisseria gonorrhoeae FbpA iron binding protein. In addition, the expression of hitB and hitC homologs was detected by Northern blot analysis. This periodontal pathogen also expresses a polypeptide homologous to the 31-kDa Haemophilus influenzae protein, which shows amino acid sequence homology with the FimA and YfeA proteins from Streptococcus parasanguis and Yersinia pestis, respectively. Both A. actinomycetemcomitans protein homologs were located within the periplasmic space, and their synthesis was regulated by the iron and hemin concentration of the culture medium. Southern and Western blot analysis together with molecular cloning revealed the presence of a Fur-like repressor, which may control the iron regulation of gene expression in this bacterium. Cultivation in the presence of hemin or Congo red revealed the ability of this organism to bind hemin. This binding activity was further confirmed by isolating Escherichia coli DH5 alpha clones that produced red and brown colonies on agar plates containing Congo red and hemin, respectively, after transformation with an A. actinomycetemcomitans gene library.
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PMID:Expression of iron binding proteins and hemin binding activity in the dental pathogen Actinobacillus actinomycetemcomitans. 967 15

The role of immunity to intracellular Ags in resistance to infection by Yersinia is not well established. The enteropathogenic bacteria Yersinia pseudotuberculosis and Yersinia enterocolitica actively translocate Ags to the cytosol of eukaryotic cells. Whereas Yersinia pestis does not always express the requisite cellular adhesins, results have varied as to whether similar cytosolic translocation of Ags occurs in vitro. We used a genetic vaccine to induce intracellular expression of the fraction 1 (F1) capsular protein of Y. pestis within host mammalian cells and examined the ensuing immune response. The F1 genetic vaccine stimulated only weak CTL responses in BALB/c mice. Substantial Ab responses to the F1 genetic vaccine were obtained in all inbred strains of mice tested, but Ab levels were less than those resulting from vaccination with the F1 polypeptide. In contrast, outbred mice did not respond to the F1 plasmid, suggesting that some inbred mouse strains may exhibit exaggerated responses to plasmid vaccines. A primary immunization with the F1 genetic vaccine followed by a boost with recombinant F1 polypeptide produced a vigorous Ab response from inbred mice that was equivalent to three injections of F1 polypeptide. We conclude that cytosolic expression of the F1 Ag efficiently primes immunity, while secondary exposure to the F1 polypeptide is required for optimal Ab induction.
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PMID:Weak anamnestic responses of inbred mice to Yersinia F1 genetic vaccine are overcome by boosting with F1 polypeptide while outbred mice remain nonresponsive. 978 Jan 93

Pathogenic Yersinia species export Yop proteins via a type III machinery to escape their phagocytic killing during animal infections. Here, we reveal the type III export mechanism of YopQ. In the presence of calcium, when type III secretion was blocked, yopQ mRNA was not translated. The signal of YopQ sufficient for the secretion of translationally fused reporter proteins was contained within the first 10 codons of its open reading frame. Some frameshift mutations that completely altered the peptide sequence specified by this signal did not impair secretion of the reporter protein. Exchanging the upstream untranslated mRNA leader of yopQ for that of E. coli lacZ also did not affect secretion. However, removal of the first 15 codons abolished YopQ export. Pulse-labelled YopE, but not YopQ, could be secreted after the polypeptide had been synthesized within the cytoplasm of Yersinia (post-translational secretion). Thus, YopQ appears to be exported by a mechanism that couples yopQ mRNA translation with the type III secretion of the encoded polypeptide.
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PMID:Yersinia enterocolitica type III secretion: an mRNA signal that couples translation and secretion of YopQ. 1009 81

The bacterial superantigens, staphylococcal enterotoxins and streptococcal pyrogenic exotoxins, are grouped in a family by the conservation of amino acid sequence and polypeptide folding patterns. In the case of Yersinia pseudotuberculosis-derived mitogen (YPM), however, there is no noticeable homology with this family, although many of the in vitro functional features conform to the criteria for a superantigen. To study the mode of action of YPM at the molecular level, we first generated a number of YPM point mutants with reduced T-cell proliferative activity using random mutagenesis and localized the amino acid positions involved in either major histocompatibility complex class II or T-cell receptor Vbeta-interaction. Plotting the elucidated positions on the hydrophilicity profile suggested that they reside mostly on the outer portion of the molecule. We also report that the two cysteines positioned almost at opposing ends of the YPM molecule are connected by an S-S bond the destruction of which causes fatal damage. Finally, we obtained evidence that YPM partially competes with staphylococcal enterotoxin E for human leukocyte antigen-DR binding. This raises the question of whether these different types of superantigens have acquired the same function by genetic convergence or originated from a common ancestral gene.
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PMID:Analysis of functional regions of YPM, a superantigen derived from gram-negative bacteria. 1040 39

Yersinia enterocolitica inject toxic proteins (effector Yops) into the cytosol of eukaryotic cells by a mechanism requiring the type III machinery. Previous work mapped a signal sufficient for the targeting of fused reporter proteins to amino acids 1-100 of YopE. Targeting requires the binding of SycE to YopE residues 15-100 in the bacterial cytoplasm. We asked whether SycE functions only to stabilize YopE in the bacterial cytoplasm, or whether the secretion chaperone itself contributes to substrate recognition by the type III machinery. Fusions of glutathione S-transferase to either the N or C terminus of SycE resulted in hybrid proteins that bound YopE but prevented targeting of the export substrate into HeLa cells. As compared with wild-type SycE, glutathione S-transferase-SycE bound and stabilized YopE in the bacterial cytoplasm but failed to release the polypeptide for export by the type III machinery. Thus, it appears that SycE functions to deliver YopE to the type III secretion machinery. A model is presented that accounts for substrate recognition of effector Yops, a group of proteins that do not share amino acid sequence or physical similarities.
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PMID:Yersinia enterocolitica type III secretion. On the role of SycE in targeting YopE into HeLa cells. 1041 39

Using a series of oligonucleotides synthesized on the basis of conserved nucleotide motifs in heat-shock genes, the groESL heat-shock operon from a Vibrio cholerae TSI-4 strain has been cloned and sequenced, revealing that the presence of two open reading frames (ORFs) of 291 nucleotides and 1,632 nucleotides separated by 54 nucleotides. The first ORF encoded a polypeptide of 97 amino acids, GroES homologue, and the second ORF encoded a polypeptide of 544 amino acids, GroEL homologue. A comparison of the deduced amino acid sequences revealed that the primary structures of the V. cholerae GroES and GroEL proteins showed significant homology with those of the GroES and GroEL proteins of other bacteria. Complementation experiments were performed using Escherichia coli groE mutants which have the temperature-sensitive growth phenotype. The results showed that the groES and groEL from V. cholerae were expressed in E. coli, and groE mutants harboring V. cholerae groESL genes regained growth ability at high temperature. The evolutionary analysis indicates a closer relationship between V. cholerae chaperonins and those of the Haemophilus and Yersinia species.
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PMID:Cloning, sequencing, and functional expression in Escherichia coli of chaperonin (groESL) genes from Vibrio cholerae. 1048 May 46

Yersinia enterocolitica is well equipped for siderophore piracy, encompassing the utilization of siderophores such as ferrioxamine, ferrichrome, and ferrienterochelin. In this study, we report on the molecular and functional characterization of the Yersinia fep-fes gene cluster orthologous to the Escherichia coli ferrienterochelin transport genes (fepA, fepDGC, and fepB) and the esterase gene fes. In vitro transcription-translation analysis identified polypeptides of 30 and 35 kDa encoded by fepC and fes, respectively. A frameshift mutation within the fepA gene led to expression of a truncated polypeptide of 40 kDa. The fepD, fepG, and fes genes of Y. enterocolitica were shown to complement corresponding E. coli mutants. Insertional mutagenesis of fepD or fes genes abrogates enterochelin-supported growth of Y. enterocolitica on iron-chelated media. In contrast to E. coli, the fep-fes gene cluster in Y. enterocolitica consists solely of genes required for uptake and utilization of enterochelin (fep) and not of enterochelin synthesis genes such as entF. By Southern hybridization, fepDGC and fes sequences could be detected in Y. enterocolitica biotypes IB, IA, and II but not in biotype IV strains, Yersinia pestis, and Yersinia pseudotuberculosis strains. According to sequence alignment data and the coherent structure of the Yersinia fep-fes gene cluster, we suggest early genetic divergence of ferrienterochelin uptake determinants among species of the family Enterobacteriaceae.
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PMID:Ferric enterochelin transport in Yersinia enterocolitica: molecular and evolutionary aspects. 1051 29

Bacterial pathogens of both animals and plants use type III secretion machines to inject virulence proteins into host cells. Although many components of the secretion machinery are conserved among different bacterial species, the substrates for their type III pathways are not. The Yersinia type III machinery recognizes some secretion substrates via a signal that is encoded within the first 15 codons of yop mRNA. These signals can be altered by frameshift mutations without affecting secretion of the encoded polypeptides, suggesting a mechanism whereby translation of yop mRNA is coupled to the translocation of newly synthesized polypeptide. We report that the type III machinery of Erwinia chrysanthemi cloned in Escherichia coli recognizes the secretion signals of yopE and yopQ. Pseudomonas syringae AvrB and AvrPto, two proteins exported by the recombinant Erwinia machine, can also be secreted by the Yersinia type III pathway. Mapping AvrPto sequences sufficient for the secretion of reporter fusions in Yersinia revealed the presence of an mRNA secretion signal. We propose that 11 conserved components of type III secretion machines may recognize signals that couple mRNA translation to polypeptide secretion.
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PMID:Reciprocal secretion of proteins by the bacterial type III machines of plant and animal pathogens suggests universal recognition of mRNA targeting signals. 1053 9

Streptogramins are polypeptide antibiotics inhibiting protein synthesis by the prokaryotic ribosome. Gram-positive organisms are susceptible to streptogramins, while most gram-negative bacteria are intrinsically resistant. We have found a genomic fragment from a Yersinia enterocolitica isolate with an open reading frame coding for a polypeptide similar to the virginiamycin acetyltransferases found in various plasmids from gram-positive bacteria. The susceptible Escherichia coli strain DB10 was transformed to resistance to the type A streptogramins and to mixed (A + B) streptogramins upon introduction of a plasmid containing that gene. In addition, we showed streptogramin acetylating activity in vitro dependent on the presence of the Y. enterocolitica sat gene. Southern blot hybridization experiments showed that the sat gene was present in all the Y. enterocolitica isolates examined. These data together show that the gene in the Y. enterocolitica chromosome encoded an active streptogramin acetyltransferase. The deduced sequence of the Y. enterocolitica Sat protein was close to those of sat gene products found in gram-positive bacteria and cyanobacteria, suggesting a common evolutionary origin.
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PMID:Identification of a streptogramin A acetyltransferase gene in the chromosome of Yersinia enterocolitica. 1072 89

The gram-negative coccobacillus, Actinobacillus actinomycetemcomitans, is the putative agent for localized juvenile periodontitis, a particularly destructive form of periodontal disease in adolescents. This bacterium has also been isolated from a variety of other infections, notably endocarditis. Fresh clinical isolates of A. actinomycetemcomitans form tenacious biofilms, a property likely to be critical for colonization of teeth and other surfaces. Here we report the identification of a locus of seven genes required for nonspecific adherence of A. actinomycetemcomitans to surfaces. The recently developed transposon IS903phikan was used to isolate mutants of the rough clinical isolate CU1000 that are defective in tight adherence to surfaces (Tad(-)). Unlike wild-type cells, Tad(-) mutant cells adhere poorly to surfaces, fail to form large autoaggregates, and lack long, bundled fibrils. Nucleotide sequencing and genetic complementation analysis revealed a 6.7-kb region of the genome with seven adjacent genes (tadABCDEFG) required for tight adherence. The predicted TadA polypeptide is similar to VirB11, an ATPase involved in macromolecular transport. The predicted amino acid sequences of the other Tad polypeptides indicate membrane localization but no obvious functions. We suggest that the tad genes are involved in secretion of factors required for tight adherence of A. actinomycetemcomitans. Remarkably, complete and highly conserved tad gene clusters are present in the genomes of the bubonic plague bacillus Yersinia pestis and the human and animal pathogen Pasteurella multocida. Partial tad loci also occur in strikingly diverse Bacteria and Archaea. Our results show that the tad genes are required for tight adherence of A. actinomycetemcomitans to surfaces and are therefore likely to be essential for colonization and pathogenesis. The occurrence of similar genes in a wide array of microorganisms indicates that they have important functions. We propose that tad-like genes have a significant role in microbial colonization.
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PMID:Nonspecific adherence by Actinobacillus actinomycetemcomitans requires genes widespread in bacteria and archaea. 1102 39


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