Role of cholesterol and polyunsaturated chains in lipid-protein interactions: molecular dynamics simulation of rhodopsin in a realistic membrane environment.
We present a 118-ns molecular dynamics simulation of rhodopsin embedded in a bilayer composed of a 2:2:1 mixture of 1-stearoyl-2-docosahexaenoyl-phosphatidylcholine (SDPC), 1-stearoyl-2-docosahexaenoyl-phosphatidylethanolamine (SDPE), and cholesterol, respectively. The simulation demonstrates that the protein breaks the lateral and transverse symmetry of the bilayer. Lipids near the protein preferentially reorient such that their unsaturated chains interact with the protein, while the distribution of cholesterol in the membrane complements the variations in rhodopsin's transverse profile. The latter phenomenon suggests a molecular-level mechanism for the experimental finding that cholesterol stabilizes the native dark-adapted state of rhodopsin without binding directly to the protein.
Pitman
Michael C
MC
IBM T. J. Watson Research Center, 1101 Kitchawan Road, P.O. Box 218, Yorktown Heights, NY 10598, USA.
Grossfield
Alan
A
Suits
Frank
F
Feller
Scott E
SE
D002784:Cholesterol / Q000737:chemistry* / Q000378:metabolism; D003198:Computer Simulation; D005231:Fatty Acids, Unsaturated / Q000737:chemistry* / Q000378:metabolism; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism; D008567:Membranes, Artificial; D008954:Models, Biological; D012243:Rhodopsin / Q000737:chemistry* / Q000378:metabolism
D005231:Fatty Acids, Unsaturated; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D012243:Rhodopsin; D002784:Cholesterol