Complementary Benzophenone Cross-Linking/Mass Spectrometry Photochemistry


Use of a heterobifunctional photoactivatable cross- linker, sulfo-SDA (diazirine), has yielded high-density data that facilitated structure modeling of individual proteins. We expand the photoactivatable chemistry toolbox here with a second reagent, sulfo- SBP (benzophenone). This further increases the density of photo- cross-linking to a factor of 20× over conventional cross-linking. Importantly, the two different photoactivatable groups display orthogonal directionality, enabling access to different protein regions, unreachable with a single cross-linker.