A fifth chloroplast‐encoded polypeptide is present in the photosystem II reaction centre complex

Abstract

The small polypeptides present in the pea photosystem II reaction centre complex have been separated by high‐resolution SDS‐polyacrylamide gel electrophoresis and characterised by N‐terminal amino acid sequencing. Two polypeptides are identified as the α‐ and β‐subunits of cytochrome b 559 which are the products of the pdb E and psb F genes. A third polypeptide, of 4.5 kDA, is identified as the product of a small open reading frame in chloroplast DNA. The gene for this polypeptide , psb I, is located just downstream of the psb K gene chloroplast DNA.