Porin threading drives receptor disengagement and enables active colicin import through OmpF

ABSTRACT: Bacteria deploy weapons to kill their neighbours during competition for resources and to aid survival within microbiomes. Colicins were the first such antibacterial system identified, yet how these bacteriocins cross the outer membrane of Escherichia coli is unknown. Here, by solving the structures of translocation intermediates via cryo-EM and by imaging toxin import, we uncover the mechanism by which the Tol-dependent nuclease colicin E9 (ColE9) crosses the outer bacterial membrane. We show that threading of ColE9's disordered domain through two pores of the trimeric porin OmpF causes the colicin to disengage from its primary receptor, BtuB, and reorganises the translocon either side of the membrane. Subsequent import of ColE9 through the lumen of a single OmpF subunit is entirely dr

SUBMITTER: Dr. Marie-Louise, R Francis 

PROVIDER: S-SCDT-EMBOJ-2021-108610 | biostudies-other |

REPOSITORIES: biostudies-other