FIG. 7.

(A) Map of the irp2 and irp1 homologous zones in E. coli CFT073, as annotated in its genome. Shown in the irp2 zone are two ORFs (black arrows), a 711-bp IS1541A-like due insertion (IS), and the primers used in PCR analyses. Shown in the irp1 zone are three ORFs (white arrows) and the modified segments S1 and S2. (B) Comparisons of S1 and S2 in Y. pestis and E. coli. In E. coli CFT073, modifications (gray) induce the lecture of stop codons (bold); in the next ORFs, the correct translation would restart downstream of the last base modification. No indication of this was found in the six YBT-producing ECOR strains, which indicates that irp1 encodes HMWP1 in these strains.