Volume-conserving trans-cis isomerization pathways in photoactive yellow protein visualized by picosecond X-ray crystallography.

ABSTRACT: Trans-to-cis isomerization, the key reaction in photoactive proteins, usually cannot occur through the standard one-bond-flip mechanism. Owing to spatial constraints imposed by a protein environment, isomerization probably proceeds through a volume-conserving mechanism in which highly choreographed atomic motions are expected, the details of which have not yet been observed directly. Here we employ time-resolved X-ray crystallography to visualize structurally the isomerization of the p-coumaric acid chromophore in photoactive yellow protein with a time resolution of 100 ps and a spatial resolution of 1.6 Å. The structure of the earliest intermediate (I(T)) resembles a highly strained transition state in which the torsion angle is located halfway between the trans- and cis-isomers. The reac

SUBMITTER: Jung YO 

PROVIDER: S-EPMC3579544 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature