PsbO is an extrinsic subunit of photosystem II, which has been proposed to play a central role in stabilization of the catalytic manganese cluster. In Arabidopsis thaliana, the PsbO proteins are encoded by two genes: psbO1(AT5G66570) and psbO2 (AT3G50820) . PsbO1 is the major isoform in Arabidopsis.
