High-pressure EPR reveals conformational equilibria and volumetric properties of spin-labeled proteins.

ABSTRACT: Identifying equilibrium conformational exchange and characterizing conformational substates is essential for elucidating mechanisms of function in proteins. Site-directed spin labeling has previously been employed to detect conformational changes triggered by some event, but verifying conformational exchange at equilibrium is more challenging. Conformational exchange (microsecond-millisecond) is slow on the EPR time scale, and this proves to be an advantage in directly revealing the presence of multiple substates as distinguishable components in the EPR spectrum, allowing the direct determination of equilibrium constants and free energy differences. However, rotameric exchange of the spin label side chain can also give rise to multiple components in the EPR spectrum. Using spin-labeled mut

SUBMITTER: McCoy J 

PROVIDER: S-EPMC3029758 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature