ABSTRACT
Host cells deploy a variety of chemically reactive small molecules, such as reactive oxygen species and reactive nitrogen species, to defend themselves against invading pathogens. These molecules are primarily known for their bactericidal activity; however, oxidants like hydrogen peroxide and nitric oxide can also function as signaling molecules that posttranslationally modify redoxsensitive amino acids under non-pathological conditions. Chemical proteomic methods rely on small-molecule, activity-based probes to facilitate the detection of reactive amino acids within a whole proteome. The indirect detection of oxidized cysteines using isoTOP-ABPP or OxICAT offers an unbiased approach to identifying OxiPTMs. Chemical profiling technologies coupled with chemotype-specific probes should help establish the contribution of specific OxiPTMs to host-microbe interactions. A recent quantitative characterization of the mouse cysteine redox proteome demonstrates the feasibility of mapping tissue-specific oxidation events in vivo. Harnessing these technologies to detect oxidative crosstalk at the host-microbe interface could uncover a vast network of ROS-mediated signaling pathways that shape bacterial and host physiology.
