The reaction center is an integral membrane protein that, together with several cofactors, mediates the primary photochemical events in bacterial photosynthesis. The amino-terminal sequences of the three subunits, L, M, and H, of the reaction center protein and the sequence of the structural gene encoding the M subunit have been reported previously. In the present study, we found that the 3' end of the structural gene encoding the L subunit overlaps by eight bases the 5' end of the gene encoding the M subunit. The primary structure of the L subunit has been determined from the nucleotide sequence of the gene and from analyses of the amino and carboxyl termini of the protein. The sequences of a number of tryptic and chymotryptic peptides were used to corroborate the nucleotide sequence. The L subunit was found to be composed of 281 amino acids (M(r) 31,319) and to contain five hydrophobic segments. It is homologous to the M subunit and to a plant thylakoid protein referred to as the Q(B) or M(r) 32,000 protein.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Issue number||23 I|
|State||Published - Jan 1 1984|
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