Colicin E1 opens its hinge to plug TolC

• DOI: 10.7554/elife.73297
• Publication Date: 2022-02-24T11:00:11Z
• Authors: S Jimmy Budiardjo; Jacqueline J Stevens; Anna L Calkins; Ayotunde P Ikujuni; Virangika K Wimal...; Emre Firlar; David A Case; Julie S Biteen; Jason T Kaelber; Joanna SG Slusky
• Keywords: Colicin; Inner membrane; Efflux; SOS response; Cell membrane

The double membrane architecture of Gram-negative bacteria forms a barrier that is impermeable to most extracellular threats. Bacteriocin proteins evolved exploit the accessible, surface-exposed embedded in outer deliver cytotoxic cargo. Colicin E1 bacteriocin produced by, and lethal to, Escherichia coli hijacks (OMPs) TolC BtuB enter cell. Here, we capture colicin translocation domain inside its receptor, TolC, by high-resolution cryo-electron microscopy obtain first reported structure bound TolC. binds stably as an open hinge through pore—an architectural rearrangement from E1’s unbound conformation. This binding stable live E. cells indicated single-molecule fluorescence microscopy. Finally, fragments plug channel, inhibiting native efflux function antibiotic pump, heightening susceptibility three classes. In addition demonstrating these protein are useful starting points for developing novel potentiators, this method could be expanded other colicins inhibit OMP functions.