Isolation and amino-terminal sequences of subunits from the photosynthetic reaction center of Rhodopseudomonas capsulata

The amino-terminal sequences have been determined by Edman degradation for the reaction center polypeptides from a carotenoidless mutant of Rhodopseudomonas capsulata. Individual polypeptides were isolated by preparative electrophoresis and electroelution. By comparison with the sequences deduced from the DNA (Youvan, D.C., Alberti, M., Begush, H., Bylina, E.J. and Hearst, J.E. (1984) Proc. Natl. Acad. Sci. USA 81, 189–192) we conclude that the M and L subunits are processed so as to remove the amino-terminal methionine, whereas the H subunit is not processed at the amino-terminus after translation. None of the subunits is synthesized with a significant amino-terminal extension peptide.