Discovery of potent charge-reducing molecules for native ion mobility mass spectrometry studies.

There is growing interest in the characterization of protein complexes and their interactions with ligands using native ion mobility mass spectrometry. A particular challenge, especially for membrane proteins, is preserving noncovalent interactions and maintaining native-like structures. Different approaches have been developed to minimize activation of protein complexes by manipulating charge on protein complexes in solution and the gas-phase. Here, we report the utility of polyamines that have exceptionally high charge-reducing potencies with some molecules requiring 5-fold less than trimethylamine oxide to elicit the same effect. The charge-reducing molecules do not adduct to membrane protein complexes and are also compatible with ion-mobility mass spectrometry, paving the way for improved methods of charge reduction.