Figure 1.

General strategy of mass spectrometric analysis of protein-protein interactions. (A) Incubate the crosslinker with the target proteins to acquire crosslinked mixtures. (B) Purify the crosslinked species by SDS-PAGE and (C) extract spots and perform in-gel, protease digestion to yield a peptide pool, which includes crosslinked and uncrosslinked peptides. (D) The peptides are submitted to mass spectrometry to acquire either MS or MS/MS data. (E) Data are subsequently analyzed.