FIG 1.

CdiA^STEC4 recognizes an uncharacterized receptor. (A) Schematic of the class IV cdiBCAI locus from E. coli STEC_O31. (B) Inhibitor cells expressing cdiBCAI^STEC4 were seeded at a 1:1 ratio with E. coli Δwzb target bacteria for coculture in broth or on solid medium. Where indicated, target cells carried a plasmid-borne copy of cdiI^STEC4. (C) Inhibitor cells expressing class I, II, III, and IV CDI systems were cocultured with E. coli Δwzb target bacteria containing the indicated mutations on agar media. The competitive index is the ratio of viable inhibitor to target cells after 3 h. Data are the averages ± SEM from at least three independent experiments.