Protein footprinting provides detailed structural information on protein structure in solution by
directly identifying accessible and hydroxyl radical-reactive side chain residues. Radiolytic
generation of hydroxyl radicals using millisecond pulses of a synchrotron" white" beam
results in the formation of stable side chain oxidation products, which can be digested with
proteases for mass spectrometry (MS) analysis. Liquid chromatography-coupled MS and
tandem MS methods allow for the quantitation of the ratio of modified and unmodified …