Transition states under pressure

Abstract

Enzyme Catalysis Enzymes are flexible and dynamic, with conformational changes in the protein, such as movement of a lid over the active site, often limiting the overall rate of turnover. Manipulating pressure offers a means of studying the transition state of processes within which the partial molar volume changes. Using model enzyme variants adapted to high or low pressure, Stiller et al. compared volume and kinetic parameters at pressures up to 50 megapascals. The piezophilic enzyme showed pressure-dependent activity resulting from hydration of the active site early in the lid-opening process. Three point mutations that disrupt a network of salt bridges that form during lid-opening can confer pressure sensitivity on the mesophilic enzyme, presumably by changing the hydration of the active site at the transition state. Nat. Catal. 10.1038/s41929-019-0307-6 (2019).