title: Small-angle scattering gives direct structural information about a membrane protein inside a lipid environment.
abstract: Monomeric bacteriorhodopsin (bR) reconstituted into POPC/POPG-containing nanodiscs was investigated by combined small-angle neutron and X-ray scattering. A novel hybrid approach to small-angle scattering data analysis was developed. In combination, these provided direct structural insight into membrane-protein localization in the nanodisc and into the protein-lipid interactions. It was found that bR is laterally decentred in the plane of the disc and is slightly tilted in the phospholipid bilayer. The thickness of the bilayer is reduced in response to the incorporation of bR. The observed tilt of bR is in good accordance with previously performed theoretical predictions and computer simulations based on the bR crystal structure. The result is a significant and essential step on the way to developing a general small-angle scattering-based method for determining the low-resolution structures of membrane proteins in physiologically relevant environments.
authors: Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark.
authors: Søren A R
authors: SA
authors: Kynde
authors: Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark.
authors: Nicholas
authors: N
authors: Skar-Gislinge
authors: Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark.
authors: Martin Cramer
authors: MC
authors: Pedersen
authors: Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark.
authors: Søren Roi
authors: SR
authors: Midtgaard
authors: Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark.
authors: Jens Baek
authors: JB
authors: Simonsen
authors: Institute Laue-Langevin, Grenoble, France.
authors: Ralf
authors: R
authors: Schweins
authors: Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark.
authors: Kell
authors: K
authors: Mortensen
authors: Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark.
authors: Lise
authors: L
authors: Arleth
mesh_terms: D019843:Archaeal Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D001436:Bacteriorhodopsins / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D006217:Halobacterium / Q000737:chemistry* / Q000378:metabolism; D008051:Lipid Bilayers / Q000737:chemistry; D008567:Membranes, Artificial; D008958:Models, Molecular; D033363:Neutron Diffraction; D010713:Phosphatidylcholines / Q000737:chemistry*; D010715:Phosphatidylglycerols / Q000737:chemistry*; D011487:Protein Conformation; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D019843:Archaeal Proteins; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D001436:Bacteriorhodopsins; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine
keywords: SANS; SAXS; Small-angle scattering; bacteriorhodopsin; membrane proteins; nanodisc