The Orange Carotenoid Protein Triggers Cyanobacterial Photoprotection by Quenching Bilins via a Structural Switch of Its Carotenoid.

ABSTRACT: Cyanobacteria were the first microorganisms that released oxygen into the atmosphere billions of years ago. To do it safely under intense sunlight, they developed strategies that prevent photooxidation in the photosynthetic membrane, by regulating the light-harvesting activity of their antenna complexes-the phycobilisomes-via the orange-carotenoid protein (OCP). This water-soluble protein interacts with the phycobilisomes and triggers nonphotochemical quenching (NPQ), a mechanism that safely dissipates overexcitation in the membrane. To date, the mechanism of action of OCP in performing NPQ is unknown. In this work, we performed ultrafast spectroscopy on a minimal NPQ system composed of the active domain of OCP bound to the phycobilisome core. The use of this system allowed us to disentang

SUBMITTER: Liguori N 

PROVIDER: S-EPMC11311238 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature