Structural homology of reaction centers from Rhodopseudomonas sphaeroides and Rhodopseudomonas viridis as determined by x-ray diffraction

James Paul Allen, G. Feher, T. O. Yeates, D. C. Rees, J. Deisenhofer, H. Michel, R. Huber

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Crystals of the reaction center (RC) from Rhodopseudomonas sphaeroides with the space group P212121, have been studied by x-ray diffraction. The Patterson search (molecular replacement) technique was used to analyze the data, with the structure of the reaction center from Rhodopseudomonas viridis as a model system. A preliminary electron density map of the reaction center from R. sphaeroides has been obtained. Comparison of the structure of the RC from R. sphaeroides with that from R. viridis showed the following conserved features: five membrane-spanning helices in each of the L and M subunits, a single membrane-spanning helix in the H subunit, a 2-fold symmetry axis, and similar positions and orientations of the cofactors. Unlike the RCs from R. viridis, both quinones are retained in the RCs from R. sphaeroides. The secondary quinone is located near the position related by the 2-fold symmetry axis to the primary quinone.

Original languageEnglish
Pages (from-to)8589-8593
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number22
Publication statusPublished - 1986


ASJC Scopus subject areas

  • Genetics
  • General

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