Plague is a flea-borne zoonosis caused by the bacterium Yersinia pestis. Y. pestis mutants lacking the yersiniabactin (Ybt) siderophore-based iron transport system are avirulent when inoculated intradermally but fully virulent when inoculated intravenously in mice. Presumably, Ybt is required to provide sufficient iron at the peripheral injection site, suggesting that Ybt would be an essential ...

Molecular analysis of 63 Escherichia coli urine isolates showed that pyelonephritis (n=23) and prostatitis (n=17) isolates exhibited more virulence factors (VFs) among the 35 sought than did cystitis isolates (n=23). Several nontraditional VFs--including bmaE (M fimbriae), gafD (G fimbriae), fyuA (yersiniabactin receptor), ireA and iroN (novel siderophore receptors), cvaC (colicin [microcin] V)...

Acyltransferases determine which extender units are incorporated into polyketide and fatty acid products. The ping-pong acyltransferase mechanism utilizes a serine in a conserved GHSxG motif. However, the role of the conserved histidine in this motif is poorly understood. We observed that a histidine to alanine mutation (H640A) in the GHSxG motif of the malonyl-CoA specific yersiniabactin acylt...

Synthesis of the siderophore yersiniabactin (Ybt) proceeds by a mixed nonribosomal peptide synthetase/polyketide synthase mechanism. Transcription of ybt genes encoding biosynthetic and transport functions is repressed under excess iron conditions by Fur, but is also activated by Ybt via the transcriptional regulator YbtA. While mutations in most biosynthetic genes and ybtA negate transcription...

Iron acquisition from the host is an important step in the pathogenic process. While Yersinia pestis has multiple iron transporters, the yersiniabactin (Ybt) siderophore-dependent system plays a major role in iron acquisition in vitro and in vivo. In this study, we determined that the Ybt system is required for the use of iron bound by transferrin and lactoferrin and examined the importance of ...

The six domain, 229 kDa HMWP2 subunit of the Yersinia pestis yersiniabactin (Ybt) synthetase has been expressed in soluble, full-length form in E. coli as a C-terminal His8 construct at low growth temperatures and with attenuated induction. All six domains of this nonribosomal peptide synthetase subunit, three phosphopantetheinylatable carrier protein domains (ArCP, PCP1, PCP2), one adenylation...