Lack of homology between the iron transport regions of two virulence-linked bacterial plasmids.

Two plasmids involved in bacterial virulence, the Escherichia coli plasmid pColV-K30 and the Vibrio anguillarum plasmid pJM1, have been studied with respect to the iron sequestering systems mediated by these two plasmids. Bioassay results show that the two systems are not related functionally because specific iron uptake-deficient mutants in each system cannot be cross-fed by the heterologous bacteria using culture supernatants from iron-proficient strains containing wild-type plasmids. DNA hybridization studies show an extensive lack of homology between regions involved in iron sequestration in both plasmids.