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Primary structure of the L subunit of the reaction center from Rhodopseudomonas sphaeroides

Williams, J. C. and Steiner, L. A. and Feher, G. and Simon, M. I. (1984) Primary structure of the L subunit of the reaction center from Rhodopseudomonas sphaeroides. Proceedings of the National Academy of Sciences of the United States of America, 81 (23). pp. 7303-7307. ISSN 0027-8424. PMCID PMC392134. doi:10.1073/pnas.81.23.7303.

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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 (Mr 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 QB or Mr 32,000 protein.

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Additional Information:© 1984 by the National Academy of Sciences. Contributed by G. Feher, August 1, 1984. We thank E. Abresch for the preparation of the RCs, L.-P. Li for assistance in peptide preparation and analysis, R.F. Doolittle for the computer alignments of homologous protein sequences, and R. Theiler and D.C. Youvan for access to unpublished material. This work was supported by grants from the National Institutes of Health (GM 07313 and 13191), the National Science Foundation (PCM 82-02811), and the Office of Naval Research (N00014-83-K-0079). The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.
Funding AgencyGrant Number
NIHGM 07313
NIHGM 13191
NSFPCM 82-02811
Office of Naval Research (ONR)N00014-83-K-0079
Subject Keywords:photosynthesis; nucleotide sequence; membrane protein; sequence comparison
Issue or Number:23
PubMed Central ID:PMC392134
Record Number:CaltechAUTHORS:WILpnas84
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10335
Deposited By: Tony Diaz
Deposited On:30 Apr 2008
Last Modified:08 Nov 2021 21:07

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