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Publication Abstract from PubMed

Membrane proteins are embedded in a lipid bilayer and maintain strong interactions with lipid molecules. Tightly bound lipids are responsible for vertical positioning and integration of proteins in the membrane, for assembly of multisubunit complexes, and occasionally act as substrates. In this work we present the lipidic-sponge phase crystal structure of the reaction center from Blastochloris viridis to 1.86 A, which reveals lipid molecules interacting with the protein surface. A diacylglycerol molecule is bound, through a thioether bond, to the N-terminus of the tetraheme cytochrome c subunit. From the electron density recovered at the QB site and the observed change in recombination kinetics in lipidic sponge phase grown crystals, the mobile ubiquinone appears to be displaced by a monoolein molecule. A 36 A long electron density feature is observed at the interface of transmembrane helices belonging to the H- and M-subunits, probably arising from an unidentified lipid.

Lipidic-sponge phase crystal structure of a photosynthetic reaction center reveals lipids on the protein surface.,Wohri AB, Wahlgren WY, Malmerberg E, Johansson LC, Neutze R, Katona G Biochemistry. 2009 Sep 10. PMID:19743880^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.