Fig. 1: CdiA-CT processing is required for translocation into the target-cell cytoplasm.
From: Proteolytic processing induces a conformational switch required for antibacterial toxin delivery
a E. coli CdiA protein domain arrangement. b Model of CdiA secretion arrest and receptor-triggered toxin delivery. c N-terminal sequences of CdiA-CTEC3006 variants used in outer-membrane bypass and in vitro tRNase assays. d Outer-membrane bypass assays. Purified CdiA-CTEC3006 variants were incubated with polymyxin B (PMB) treated E. coli cells. Total RNA was isolated for Northern blot analysis using a probe to tRNAIle. e In vitro nuclease assays. E. coli total RNA was treated with purified CdiA-CTEC3006 in the absence and presence of CdiIEC3006. Reactions were analyzed by Northern blotting using a probe to tRNAIle. f CdiA-CTEC3006 entry depends on PtsG and the proton gradient. Purified ∆VENN CdiA-CTEC3006 was incubated with E. coli ∆ptsG and ptsG+ cells treated with PMB and carbonyl cyanide-m-chlorophenylhydrazone (CCCP). Where indicated, cells also carried plasmids that encode PtsG and CdiIEC3006. Total RNA was isolated and analyzed by Northern blotting using a probe to tRNAIle. Experiments depicted in panels d–f were repeated independently twice with similar results. CCCP carbonyl cyanide m-chlorophenylhydrazone, CE cytoplasm entry, CM cytoplasmic membrane, FHA filamentous hemagglutinin, nt nucleotides, PMB polymyxin B, PT pretoxin, RBD receptor-binding domain, ss signal sequence, tox toxin, YP tyrosine-proline enriched. Source data are provided as a Source Data file.
