Time-Dependent Labeling of Proteins by Fast Photochemical Oxidation of Proteins (FPOP)

摘要

FPOP is an MS-based protein footprinting approach that uses a pulsed laser to photolyze H_2O_2 to OH and modify proteins on the microsecond timescale. The estimated labeling time, based on known rate constants, is ～1 μs, a timescale sufficiently short to label only one protein conformation [2]. High speed of FPOP makes feasible an MS-based means of protein footprinting and protein-folding monitoring on that timescale [3]. Typical, previously established parameters that lead to 1 μs labeling are 15 mM H_2O_2, 20 mM glutamine, 10 μM protein, 40 mJ/pulse laser energy.