title: X-ray structure of bacteriorhodopsin at 2.5 angstroms from microcrystals grown in lipidic cubic phases.
abstract: Lipidic cubic phases provide a continuous three-dimensional bilayer matrix that facilitates nucleation and growth of bacteriorhodopsin microcrystals. The crystals diffract x-rays isotropically to 2.0 angstroms. The structure of this light-driven proton pump was solved at a resolution of 2.5 angstroms by molecular replacement, using previous results from electron crystallographic studies as a model. The earlier structure was generally confirmed, but several differences were found, including loop conformations and side chain residues. Eight water molecules are now identified experimentally in the proton pathway. These findings reveal the constituents of the proton translocation pathway in the ground state.
authors.affiliation: Institut de Biologie Structurale/CEA-CNRS/Université Joseph Fourier, 41 Avenue des Martyrs, F-38027 Grenoble Cedex 1, France.
authors.forename: E
authors.initials: E
authors.lastname: Pebay-Peyroula
authors.forename: G
authors.initials: G
authors.lastname: Rummel
authors.forename: J P
authors.initials: JP
authors.lastname: Rosenbusch
authors.forename: E M
authors.initials: EM
authors.lastname: Landau
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray / Q000379:methods*; D003593:Cytoplasm / Q000737:chemistry; D005989:Glycerides; D006217:Halobacterium / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017494:Proton Pumps; D011522:Protons; D012172:Retinaldehyde / Q000737:chemistry; D012545:Schiff Bases; D017356:Synchrotrons; D014867:Water
chemical_list: D005989:Glycerides; D017494:Proton Pumps; D011522:Protons; D012545:Schiff Bases; D014867:Water; D001436:Bacteriorhodopsins; C005953:monoolein; D012172:Retinaldehyde