Quantitative proteome of bacterial periplasmic predation by Bdellovibrio bacteriovorus reveals a prey-lytic protease.

The rise of antimicrobial resistant pathogens calls for novel ways to kill and damage bacteria. A rich source for bacterial cell-damaging proteins is the periplasmic predatory bacterium Bdellovibrio bacteriovorus, which invades, kills and subsequently exits the prey cell. An increased understanding of predatory protein function can be achieved by analyzing their relative abundance at key stages of predation. We present the first quantitative proteome covering the complete predatory life cycle of B. bacteriovorus killing Escherichia coli, quantifying 2195 predator proteins. Protein clustering reveals nine distinct clusters sharing similar expression patterns. Notably, the protease Bd2269 is highly abundant during the prey exit phase. Gene knockout and heterologous expression experiments reveal that Bd2269 is involved in the prey exit process and lyses E. coli from within. Our quantitative predator proteome is a valuable resource to study specific stages of the predatory life cycle, contributing to advancing the search for novel antimicrobial enzymes.