ABSTRACT
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 theYersinia fep-fes gene cluster orthologous to theEscherichia 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 byfepC 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 orfes genes abrogates enterochelin-supported growth ofY. enterocolitica on iron-chelated media. In contrast toE. coli, the fep-fes gene cluster inY. 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, andYersinia 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 familyEnterobacteriaceae.
Characterization of a plasmid-encoded urease gene cluster found in members of the family Enterobacteriaceae.