High Order Protein Structure by Mass Spectrometry Methods: Structural Mass Spectrometry

Mass spectrometry, as the enabling tool for proteomics, is well-established to provide primary structure on proteins, revolutionizing protein science. Our interest is a higher-order structure. David Hambly of my lab developed a free-radical footprinting approach we term “fast photochemical oxidation of proteins” or FPOP. FPOP provides fast, microsecond labeling of proteins. Its speed allows reports on hidden conformations of proteins and on fast-folding. FPOP is also useful for mapping epitopes, following aggregation of proteins in neurodegeneration, and affinity measurements for signaling proteins. We are complementing FPOP by implementing extensions of hydrogen-deuterium exchange for reporting on pH changes, protein aggregation, and affinity. Both HDX and FPOP, when integrated with native MS and cross-linking make a compelling approach that is becoming known as “structural mass spectrometry.”