Photoactivation Mechanism, Timing of Protein Secondary Structure Dynamics and Carotenoid Translocation in the Orange Carotenoid Protein.

ABSTRACT: The orange carotenoid protein (OCP) is a two-domain photoactive protein that noncovalently binds an echinenone (ECN) carotenoid and mediates photoprotection in cyanobacteria. In the dark, OCP assumes an orange, inactive state known as OCP^O; blue light illumination results in the red active state, known as OCP^R. The OCP^R state is characterized by large-scale structural changes that involve dissociation and separation of C-terminal and N-terminal domains accompanied by carotenoid translocation into the N-terminal domain. The mechanistic and dynamic-structural relations between photon absorption and formation of the OCP^R state have remained largely unknown. Here, we employ a combination of time-resolved UV-visible and (polarized) mid-infrared spectr

SUBMITTER: Konold PE 

PROVIDER: S-EPMC6331140 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature