Gas-Phase Collisions with Trimethylamine-N-Oxide Enable Activation-Controlled Protein Ion Charge Reduction.

ABSTRACT: Modulating protein ion charge is a useful tool for the study of protein folding and interactions by electrospray ionization mass spectrometry. Here, we investigate activation-dependent charge reduction of protein ions with the chemical chaperone trimethylamine-N-oxide (TMAO). Based on experiments carried out on proteins ranging from 4.5 to 35 kDa, we find that when combined with collisional activation, TMAO removes approximately 60% of the charges acquired under native conditions. Ion mobility measurements furthermore show that TMAO-mediated charge reduction produces the same end charge state and arrival time distributions for native-like and denatured protein ions. Our results suggest that gas-phase collisions between the protein ions and TMAO result in proton transfer, in line with previ

SUBMITTER: Kaldmae M 

PROVIDER: S-EPMC6669196 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature