Inhibition of oxygen evolution in Photosystem II by Cu(II) ions is associated with oxidation of cytochrome b559.

ABSTRACT: We have found that elevated copper concentrations, apart from the inhibition of oxygen evolution, changed the initial states distribution of the oxygen-evolving complex. Already at low concentrations, copper ions oxidized the low-potential form of cytochrome b (559) and also its high-potential form at higher concentrations at which fluorescence quenching was observed. We suggest that the primary target sites in Photosystem II for copper is tyrosine(z), both cytochrome b (559) forms and chlorophyll(z), and that these sites are the source of the copper-induced fluorescence quenching and oxygen evolution inhibition in Photosystem II.

SUBMITTER: Burda K 

PROVIDER: S-EPMC1223302 | biostudies-other | 2003 Apr

REPOSITORIES: biostudies-other