Bicelle crystallization: a new method for crystallizing membrane proteins yields a monomeric bacteriorhodopsin structure.
Obtaining crystals of membrane proteins that diffract to high resolution remains a major stumbling block in structure determination. Here we present a new method for crystallizing membrane proteins from a bicelle forming lipid/detergent mixture. The method is flexible and simple to use. As a test case, bacteriorhodopsin (bR) from Halobacterium salinarum was crystallized from a bicellar solution, yielding a new bR crystal form. The crystals belong to space group P2(1) with unit cell dimensions of a=45.0 A, b=108.9 A, c=55.9 A, beta=113.58 degrees and a dimeric asymmetric unit. The structure was solved by molecular replacement and refined at 2.0 A resolution. In all previous bR structures the protein is organized as a parallel trimer, but in the crystals grown from bicelles, the individual bR subunits are arranged in an antiparallel fashion.
Faham
Salem
S
Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1570, USA.
Bowie
James U
JU
D001436:Bacteriorhodopsins / Q000737:chemistry* / Q000378:metabolism*; D003460:Crystallization; D003902:Detergents / Q000378:metabolism*; D019617:Halobacterium salinarum / Q000737:chemistry*; D050356:Lipid Metabolism; D008958:Models, Molecular; D011487:Protein Conformation; D012996:Solutions; D014961:X-Ray Diffraction
D003902:Detergents; D012996:Solutions; D001436:Bacteriorhodopsins