Topological Study of Membrane Proteins by Mass Spectrometry

Many static protein structures have been determined by X-ray crystallography and nuclear magnetic resonance (NMR). Protein dynamics has also been studied. The structure and dynamics of proteins provide critical information about their functional mechanisms. Recently, mass spectrometry has become an essential method to analyze protein topological structures and protein dynamics. We performed topological analysis of membrane proteins using mass spectrometry coupled with chemical cross-linking. The combination of chemical cross-linking and mass spectrometry is a powerful method for analyzing the topological organization of protein structures, protein complexes, and the interface between interacting subunits. In this paper, we introduce our strategies for studying the membrane-protein and protein-protein interaction sites of P450 17α with its redox partners, NADPH-cytochrome P450 reductase and cytochrome b5.