An oxygen‐evolving complex with a simple subunit structure ‐ ‘a water‐plastoquinone oxidoreductase” ‐ from the thermophilic cyanobacterium<i>Synechococcus</i>sp.

Abstract

An oxygen‐evolving complex has been highly purified from the thermophilic cyanobacterium Synechococcus sp. The complex, which reproducibly showed 5 major polypeptide bands of 47, 40, 35, 30 and 9 kDa on SDS‐polyacrylamide gel electrophoresis and contained 3.2 Mn per Q A , had an oxygen‐evolving activity of 300–400 chl per h in the presence of 5 mM MnCl 2 ; or CaCl 2 . The complex most likely represents a minimum functional unit of the photosynthetic oxygen evolution.