Two-Photon-Driven Photoprotection Mechanism in Echinenone-Functionalized Orange Carotenoid Protein.

ABSTRACT: Orange carotenoid protein (OCP) is a photoactive protein that mediates photoprotection in cyanobacteria. OCP binds different ketocarotenoid chromophores such as echinenone (ECN), 3'- hydroxyechinenone (hECN), and canthaxanthin (CAN). In the dark, OCP is in an inactive orange form known as OCP^O; upon illumination, a red active state is formed, referred to as OCP^R, that can interact with the phycobilisome. Large gaps still exist in the mechanistic understanding of the events between photon absorption and formation of the OCP^R state. Recent studies suggested that more than one photon may be absorbed during the photocycle. Using a two-pulse excitation setup with variable time delays between the pulses, we demonstrate that canthaxanthin-functionalized OCP^O<

SUBMITTER: Nizinski S 

PROVIDER: S-EPMC11803624 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature