Programmed Secretion Arrest and Receptor-Triggered Toxin Export during Antibacterial Contact-Dependent Growth Inhibition.

ABSTRACT: Contact-dependent growth inhibition (CDI) entails receptor-mediated delivery of CdiA-derived toxins into Gram-negative target bacteria. Using electron cryotomography, we show that each CdiA effector protein forms a filament extending ∼33 nm from the cell surface. Remarkably, the extracellular filament represents only the N-terminal half of the effector. A programmed secretion arrest sequesters the C-terminal half of CdiA, including the toxin domain, in the periplasm prior to target-cell recognition. Upon binding receptor, CdiA secretion resumes, and the periplasmic FHA-2 domain is transferred to the target-cell outer membrane. The C-terminal toxin region of CdiA then penetrates into the target-cell periplasm, where it is cleaved for subsequent translocation into the cytoplasm. Our findings

SUBMITTER: Ruhe ZC 

PROVIDER: S-EPMC6333426 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature