Phosphotylatíon of some polypeptides of photosystem 2 (PS2) core was observed for chloroplasts phosphoiylated under anaerobic conditions. These polypeptides appeared in the photosystem 1 (PSI) paiticles isolated from phosphorylated chloroplasts. Phosphorylated PS2 was transferred onto PSI as an integrál complex, which retained photochemical activity and originated variable fluorescence.