Arnoux B, Ducruix A, Astier C, Picaud M, Roth M, Reiss-Husson F. Towards the understanding of the function of Rb sphaeroides Y wild type reaction center: gene cloning, protein and detergent structures in the three-dimensional crystals.
Biochimie 1990;
72:525-30. [PMID:
2126457 DOI:
10.1016/0300-9084(90)90116-x]
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Abstract
We report various experiments aimed at the resolution of the 3-dimensional structure of the photosynthetic reaction center from wild type Y Rhodobacter sphaeroides. The genes encoding the L and M polypeptides have been cloned and sequenced. They bear 2 mutations each when compared to those already sequenced in another Rb sphaeroides strain (2.4.1). In the L gene, these codon changes are silent. In the M gene, one is silent and the other one leads to a Leu-Met substitution at position 140. At the present stage of the refinement of the X-ray data (0.3 nm resolution) the structure of the Y reaction center is shown to be highly similar to that of the Rhodopseudomonas viridis reaction center. The binding of spheroidene on the M side of the Y reaction center is shown to be determined by hydrophobic interactions with neighboring amino acids and by steric factors. Preliminary results concerning the localization of the detergent (beta-octylglucoside) in the unit cell are presented. This method combines low angle neutron scattering at different contrasts in H2O/D2O with X-ray crystallographic data.
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