MALDI Peptide Mapping for Fast Analysis in Protein Footprinting.

Although protein footprinting results are commonly obtained by ESI-based LC-MS/MS, a more rapid-turnaround alternative approach is desirable to expand the scope of protein footprinting and facilitate routine analysis such as monitoring protein high order structure in quality control or checking epitope maps. Considering that MALDI is a faster procedure that can be easily adapted for high-throughput analysis, we explore here the feasibility of developing a MALDI-based analysis "portfolio" of bottom-up peptide mass mapping for footprinting. The approach was applied to several model proteins that were submitted to two footprinting strategies, FPOP and GEE labeling, and their performance was evaluated. We found adequate coverage that can be improved with automatic off-line separation and spotting, demonstrating the capability to footprint accurately protein conformational change, showing that MALDI may be useful for selected applications in protein footprinting.