Oral Presentation The 6th Prato Conference on Pore Forming Proteins 2025

Bacteriodales that thrive in the gut microbiotia are vital for host health. This ecosystem is balanced by fierce competition, where Bacteriodales have developed specialised weapons that destroy rival bacteria. These Bacteriodales Secreted Antimicrobial Protein (BSAP) toxins target specific membrane receptors that are critical for bacterial colonisation and therefore continue to be maintained through replication, representing a potential target for antimicrobials. While it is clear that BSAPs are strong ecological drivers, little is known about their specificity of interactions and mechanisms of targeting killing. Using cryoEM and bacterial killing assays, we define the molecular drivers that underpin receptor recognition and how this drives toxin oligomerisation and membrane binding to ultimate destroy their target.