Proline 54 trans-cis isomerization is responsible for the kinetic partitioning at the last-step photocycle of photoactive yellow protein.

ABSTRACT: Photoactive yellow protein (PYP), a blue-light photoreceptor for Ectothiorhodospira halophila, has provided a unique system for studying protein folding that is coupled with a photocycle. Upon receptor activation by blue light, PYP proceeds through a photocycle that includes a partially folded signaling state. The last-step photocycle is a thermal recovery reaction from the signaling state to the native state. Bi-exponential kinetics had been observed for the last-step photocycle; however, the slow phase of the bi-exponential kinetics has not been extensively studied. Here we analyzed both fast and slow phases of the last-step photocycle in PYP. From the analysis of the denaturant dependence of the fast and slow phases, we found that the last-step photocycle proceeds through parallel chann

SUBMITTER: Lee BC 

PROVIDER: S-EPMC2590911 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature