Amino acid oxidation of the D1 and D2 proteins by oxygen radicals during photoinhibition of Photosystem II.

ABSTRACT: The Photosystem II reaction center is vulnerable to photoinhibition. The D1 and D2 proteins, lying at the core of the photosystem, are susceptible to oxidative modification by reactive oxygen species that are formed by the photosystem during illumination. Using spin probes and EPR spectroscopy, we have determined that both O₂^•- and HO^• are involved in the photoinhibitory process. Using tandem mass spectroscopy, we have identified a number of oxidatively modified D1 and D2 residues. Our analysis indicates that these oxidative modifications are associated with formation of HO^• at both the Mn₄O₅Ca cluster and the nonheme iron. Additionally, O₂^•- appears to be formed by the reduction of O₂ at eit

SUBMITTER: Kale R 

PROVIDER: S-EPMC5358366 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature