Gas-phase folding and unfolding of cytochrome c cations.

Wood, T D; Chorush, R A; Wampler, F M; Little, D P; O'Connor, P B; McLafferty, F W · Proc Natl Acad Sci U S A · 1995

basic_science · Level V

Where this comes from

Abstract

Water is thought to play a dominant role in protein folding, yet gaseous multiply protonated proteins from which the water has been completely removed show hydrogen/deuterium (H/D) exchange behavior similar to that used to identify conformations in solution. Indicative of the gas-phase accessibility to D2O, multiply-charged (6+ to 17+) cytochrome c cations exchange at six (or more) distinct levels of 64 to 173 out of 198 exchangeable H atoms, with the 132 H level found at charge values 8+ to 17+. Infrared laser heating and fast collisions can apparently induce ions to unfold to exchange at a higher distinct level, while charge-stripping ions to lower charge values yields apparent folding as well as unfolding.

Medical subject headings