Antibodies raised against each of the constituent proteins of the photosystem II core complex, i.e. against the 47 kDa protein (psbB product), the 43 kDa protein (psbC product), cytochrome b-559 (psbE and psbF products), the psbA product expressed in E. coli or against a synthetic oligopeptide corresponding to a part of the sequence of psbD gene, were utilized to determine the origin of higher molecular mass bands exhibited by SDS-polyacrylamide gel electrophoresis of photosystem II preparations, and to identify the two medium-size polypeptides in the 30 kDa region of the recently isolated photosystem II reaction center [(1987) Proc. Natl. Acad. Sci. USA 84, 109–112]. The result of analysis clearly indicated that the photosystem II reaction center consists entirely of D-1 (psbA product), D-2 (psbD product) and cytochrome b-559.
