Profiling the Heme‐Binding Proteomes of Bacteria Using Chemical Proteomics

Abstract

Heme is a cofactor with myriad roles and essential to almost all living organisms. Beyond classical gas transport and catalytic functions, heme is increasingly appreciated as a tightly controlled signalling molecule regulating protein expression. However, heme acquisition, biosynthesis and regulation is poorly understood beyond a few model organisms, and the heme‐binding proteome has not been fully characterised in bacteria. Yet as heme homeostasis is critical for bacterial survival, heme‐binding proteins are promising drug targets. Herein we report a chemical proteomics method for global profiling of heme‐binding proteins in live cells for the first time. Employing a panel of heme‐based clickable and photoaffinity probes enabled the profiling of 32–54 % of the known heme‐binding proteomes in Gram‐positive and Gram‐negative bacteria. This simple‐to‐implement profiling strategy could be interchangeably applied to different cell types and systems and fuel future research into heme biology.