On the Width of Conformational Transitions of Biologically Important Macromolecules under the Influence of Pressure

Abstract

Abstract—A theoretical assessment of the half-width of the conformational transition of macromolecules caused by an increase in pressure is presented. It is shown that the half-width is determined mainly by the change (jump) of the volume during the transition. A formula similar to van-Goff’s formula for the half-width of transitions caused by temperature increase is obtained, which makes it possible to estimate the effective change in volume for a one-stage transition under the influence of pressure by its half-width. The estimates show that the “gel–liquid crystal” transitions in phospholipids have a half-width of several megapascals (tens of atmospheres), while in proteins it is approximately 100 times higher and equals hundreds of megapascals (several thousand atmospheres). It is shown that the volume jump can significantly change in the interval from the beginning to the end of the transition during denaturation of proteins under the influence of pressure.