In vitro expression of a 22-kilodalton Yersinia pestis polypeptide immunologically related to the 25-kilodalton plasmid-encoded protein of the three pathogenic Yersinia species

Abstract

Antibodies raised against the 25-kilodalton (p25) plasmid-encoded polypeptide of Yersinia enterocolitica recognized the homologous protein in the three Yersinia species grown in vitro. This polypeptide was recovered from whole cells as well as from the fluid supernatant of bacteria grown at 37°C in a Ca2+-deficient medium. Furthermore, a 22-kilodalton (p22) plasmid-encoded polypeptide immunologically related to p25 was found only in Y. pestis during early growth. After 30 h of culture, the Y. pestis p25 and p22 were completely degraded, whereas the intensity of the Y. enterocolitica p25 was decreased, but the protein was still detectable in the fluid supernatant. This proteolytic activity was independent of the presence of the virulence plasmid. Some disulfide bonds are probably involved in the quaternary structure of the p25 of the three pathogenic species and of the Y. pestis p22.

Expression of the Plague Plasminogen Activator inYersinia pseudotuberculosisandEscherichia coli

“…First, at least portions of the process occurred more rapidly in Y. pestis, even though the specific activities of Pla in the two isolates were equivalent as determined by fibrinolytic assay. This phenomenon is illustrated by the prompt disappearance of YopE in Pst ϩ cells of Y. pestis KIM with immediate conversion to its stable derivative (13), as opposed to more leisurely degradation in Lcr ϩ Pst ϩ cells of Y. pseudotuberculosis PB1. Second, YadA of the latter underwent evident Plamediated alteration, resulting in the appearance of four distinct structural elements, with the molecular mass of the largest equal to that of native YadA in the Lcr ϩ Pst Ϫ control.…”

“…Native Yops did not accumulate in wild-type cells of Y. pestis grown in a Ca 2ϩ -deficient environment that favored their net synthesis by Y. pseudotuberculosis (61), although analysis of unprocessed Lcr ϩ cells of Y. pestis grown in vitro revealed a large segment of YopE (13). Upon pulsing Ca 2ϩ -starved plague bacilli with [ 35 S]methionine, radioactivity immediately appeared in a complete complement of native Yops but was promptly chased into small peptides (43,56), except for a stable fragment of YopE probably identical to that noted above (13). This posttranslational degradation was attributed to the action of Pla (56,57), a conclusion later verified by genetic analysis (60).…”

Identification of additional virulence determinants on the pYV plasmid of Yersinia enterocolitica W227

“…These Yops appear to be highly conserved in the three species. Most of them were shown to have similar molecular masses and to be immunologically related (3,8,20,21,36). Sequence data show that gene yop5l from Y. enterocolitica, encoding a 50,882-dalton (Da) protein, is 99% homologous with yopH (encoding Yop2b), its counterpart from Y. pseudotuberculosis (5, 28a).…”