Fast Photochemical Oxidation of Proteins Coupled with Mass Spectrometry.

Structural proteomics approaches coupled with mass spectrometry are increasingly used in biology to examine the composition and structure of macromolecules. Hydroxyl radical-mediated protein footprinting using mass spectrometry has recently been developed to define structure, assembly, and conformational changes of macromolecules in solution based on measurements of reactivity of amino-acid side chains with reagents that irreversibly modify a protein side chain. Generating the hydroxyl radicals by laser irradiation, Hambly and Gross developed fast photochemical oxidation of proteins (FPOP), which labels proteins on the millisecond or shorter time scale. Quantitative mass spectrometric analysis of the modified protein fragments provide a footprinting approach that has been used to probe protein structure and protein-ligand and protein-protein interactions. In this review, we discuss the fundamentals of the FPOP method and review its application in protein footprinting. We also will highlight the future directions of FPOP.