Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

OmpT is a protease associated with the outer membrane of Escherichia coli and possesses a high degree of homology to the plasminogen activator, Pla, of Yersinia pestis. We show here that OmpT from intact cells can indeed activate plasminogen. Clinical specimens of E. coli were examined for protease activity and for the ompT gene. Few isolates (12%) were found to be positive for OmpT activity, whereas most (77%) carried the ompT gene and expressed the cloned protease gene. In this report we present evidence suggesting that the surface architecture of E. coli influences the activity of OmpT and that OmpT may be indicative of the pathogenic potential of the organism.
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PMID:Prevalence of ompT among Escherichia coli isolates of human origin. 142 4

A 9.5-kilobase plasmid of Yersinia pestis, the causative agent of plague, is required for high virulence when mice are inoculated with the bacterium by subcutaneous injection. Inactivation of the plasmid gene pla, which encodes a surface protease, increased the median lethal dose of the bacteria for mice by a millionfold. Moreover, cloned pla was sufficient to restore segregants lacking the entire pla-bearing plasmid to full virulence. Both pla+ strains injected subcutaneously and pla- mutants injected intravenously reached high titers in liver and spleen of infected mice, whereas pla- mutants injected subcutaneously failed to do so even though they establish a sustained local infection at the injection site. More inflammatory cells accumulated in lesions caused by the pla- mutants than in lesions produced by the pla+ parent. The Pla protease was shown to be a plasminogen activator with unusual kinetic properties. It can also cleave complement C3 at a specific site.
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PMID:A surface protease and the invasive character of plague. 143 93

A genomic library of Yersinia pestis EV76c created in a cosmid vector was screened for clones capable of binding type IV collagen. An unexpectedly high number of such clones was observed. One recombinant plasmid was selected for further study, and the locus controlling collagen binding was mapped by subcloning, transposon mutagenesis and exonuclease digestion. The outer-membrane protein profiles of transposon insertion mutants were correlated with phenotype to implicate a 36 kDa polypeptide in type IV collagen binding. Fine substructure restriction mapping and limited DNA sequence analysis showed the cloned locus to be identical to the locus (pla) for the plasminogen activator, previously characterized genetically and biochemically. The pla locus is resident on a 9.5 kb plasmid in wild-type Y. pestis strains. Curing of this plasmid resulted in negligible reduction in collagen-binding capacity, implying the existence of a chromosomally located determinant for collagen binding. The affinity of the plasminogen activator for collagen was relatively weak. When the cloned pla locus was introduced into E. coli, it conferred upon the cell the ability to bind to cells from a number of cell lines. Binding to glycolipids separated by thin-layer chromatography demonstrated that the receptor was a member of the globo-series of glycolipids. Since it has been reported that mutation of pla dramatically reduces virulence, we propose that this hitherto undescribed function of the gene product could contribute to the biological activities necessary for full virulence.
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PMID:Adhesive properties conferred by the plasminogen activator of Yersinia pestis. 152 8

We have determined the nucleotide sequence of the 1.4-kilobase DNA fragment containing the plasminogen activator gene (pla) of Yersinia pestis, which determines both plasminogen activator and coagulase activities of the species. The sequence revealed the presence of a 936-base-pair open reading frame that constitutes the pla gene. This reading frame encodes a 312-amino-acid protein of 34.6 kilodaltons and containing a putative 20-amino-acid signal sequence. The presence of a single large open reading frame is consistent with our previous conclusion that the two Pla proteins which appear in the outer membrane of pla+ Y. pestis are derived from a common precursor. The deduced amino acid sequence of Pla revealed that it possesses a high degree of homology to the products of gene E of Salmonella typhimurium and ompT of Escherichia coli but does not possess significant homology to other plasminogen activators of known sequence. We also identified a transcription unit that resides on the complimentary strand and overlaps the pla gene.
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PMID:Nucleotide sequence of the plasminogen activator gene of Yersinia pestis: relationship to ompT of Escherichia coli and gene E of Salmonella typhimurium. 265 10

Pathogenic yersiniae undergo an established low calcium response (LCR) at 37 degrees C in Ca2+-deficient media characterized by restricted growth with synthesis of Lcr plasmid-encoded virulence functions. The latter include outer membrane peptides (Yops) known to undergo Pst plasmid-mediated post-translational degradation in Yersinia pestis but not in enteropathogenic yersiniae lacking this plasmid. Salient Yops of Y. pestis are shown here to be either maintained in the steady state or to exist as a stable degradation product (p24 of Yop E). Processing of plague plasminogen activator (p36 to p33), responsible for hydrolysis of Yops, required 2 h. Avirulence of mutants with inserted Mu dl1 (Apr lac) in yopE was verified and shown to occur independently of introduced fusion-dependent peptides. However, avirulence of such yopE mutants but not that of isolates lacking the Lcr plasmid was phenotypically suppressed in mice injected with iron. Appearance of 20,500 and 40,500 Da heat-shock peptides preceded onset of the LCR. Lcr plasmid mediated V antigen (p38) and p20, Pst plasmid-encoded p36, and chromosomally promoted p56 and p70 were synthesized throughout the LCR. Classical antigen 5 was equated with p70 which was shared by Yersinia pseudotuberculosis but not Yersinia enterocolitica.
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PMID:Expression of the low calcium response in Yersinia pestis. 273 60

The 9.5-kilobase plasmid of Yersinia pestis determines plasminogen activator, coagulase, pesticin, and pesticin immunity activities. We have mapped and cloned the loci encoding these activities and demonstrated that both plasminogen activator and coagulase were determined by the same gene, designated pla. The primary translation product of this gene (38 kilodaltons [kDa]) was processed in two sequential steps to produce peptides of 37 and 35 kDa. The first step in this processing occurred rapidly and probably cotranslationally and was blocked when protein export was inhibited. The second step was much slower and resulted in the presence of both the 37- and 35-kDa species in significant quantities. We also showed that the plasmid had a polA-dependent replicon and identified the region that contained its origin of replication and incompatibility functions.
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PMID:Genetic analysis of the 9.5-kilobase virulence plasmid of Yersinia pestis. 284 70

The related family of virulence plasmids found in the three major pathogens of the genus Yersinia all have the ability to encode a set of outer membrane proteins. In Y. enterocolitica and Y. pseudotuberculosis, these proteins are major constituents of the outer membrane when their synthesis is fully induced. In contrast, they have been difficult to detect in Y. pestis. It has recently been established that Y. pestis does synthesize these proteins, but that they are rapidly degraded due to some activity determined by the 9.5-kilobase plasmid commonly found in Y. pestis strains. We show that mutations in the pla gene of this plasmid, which encodes both the plasminogen activator and coagulase activities, blocked this degradation. A cloned 1.4-kilobase DNA fragment carrying pla was also sufficient to cause degradation in the absence of the 9.5-kilobase plasmid.
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PMID:Plasminogen activator/coagulase gene of Yersinia pestis is responsible for degradation of plasmid-encoded outer membrane proteins. 284 71

Yersinia pestis, the plague bacillus, infects a variety of mammals throughout the world and is transmitted by fleas. We developed a polymerase chain reaction (PCR) test using primers designed from the Y. pestis plasminogen activator gene to directly detect plague-infected fleas. As few as 10 Y. pestis cells were detected, even in the presence of flea tissue, by PCR and then agarose gel electrophoresis and ethidium bromide staining. The feasibility of the assay was demonstrated by using naturally infected Xenopsylla cheopis fleas. The detection of Y. pestis in fleas by PCR provides a rapid and sensitive way to monitor plaque in wild animal populations, allowing public health officials to better assess the potential risk of transmission to humans.
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PMID:New method for plague surveillance using polymerase chain reaction to detect Yersinia pestis in fleas. 831 93

It is established that the medically significant yersiniae require the presence of physiological levels of Ca2+ (ca. 2.5 mM) for sustained growth at 37 degrees C and that this nutritional requirement is mediated by a shared ca. 70-kb Lcr plasmid. The latter also encodes virulence factors (Yersinia outer membrane proteins [Yops] and V antigen) known to be selectively synthesized in vitro at 37 degrees C in Ca(2+)-deficient medium. In this study, cells of Yersinia pestis KIM were first starved for Ca2+ at 37 degrees C to prevent synthesis of bulk vegetative protein and then, after cell division had ceased, pulsed with [35S]methionine. After sufficient chase to ensure plasminogen activator-mediated degradation of Yops, the remaining major radioactive peptides were separated by conventional chromatographic methods and identified as Lcr plasmid-encoded V antigen and LcrH (and possibly LcrG), ca. 10-kb Pst plasmid-encoded pesticin and plasminogen activator, ca. 100-kb Tox plasmid-encoded fraction 1 (capsular) antigen and murine exotoxin, and chromosomally encoded antigen 4 (pH 6 antigen) and antigen 5 (a novel hemin-rich peptide possessing modest catalase activity but not superoxide dismutase activity). Also produced at high concentration was a chromosome-encoded GroEL-like chaperone protein. Accordingly, the transcriptional block preventing synthesis of bulk vegetative protein at 37 degrees C in Ca(2+)-deficient medium may not apply to genes encoding virulence factors or to highly conserved GroEL (known in other species to utilize a secondary stress-induced sigma factor).
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PMID:Major stable peptides of Yersinia pestis synthesized during the low-calcium response. 841 35

We developed a 4-h nested polymerase chain reaction assay that detected a region of the plasminogen activator gene of Yersinia pestis in 100% of 43 Y. pestis strains isolated from humans, rats, and fleas yet was unreactive with the closely related species Yersinia enterocolitica and Yersinia pseudotuberculosis.
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PMID:Rapid and specific identification of Yersinia pestis by using a nested polymerase chain reaction procedure. 845 80


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