title: Reconstitution and alignment by a magnetic field of a beta-barrel membrane protein in bicelles.
abstract: A protocol is described for the reconstitution of a transmembrane beta-barrel protein domain, tOmpA, into lipid bicelles. tOmpA is the largest protein to be reconstituted in bicelles to date. Its insertion does not prevent bicelles from orienting with their plane either parallel or perpendicular to the magnetic field, depending on the absence or presence of paramagnetic ions. In the latter case, tOmpA is shown to align with the axis of the beta-barrel parallel to the magnetic field, i.e. perpendicular to the plane of the bilayer, an orientation conforming to that in natural membranes and favourable to structural studies by solid-state NMR. Reconstitution into bicelles may offer an interesting approach for structural studies of membrane proteins in a medium resembling a biological membrane, using either NMR or other biophysical techniques. Our data suggest that alignment in the magnetic field of membrane proteins included into bicelles may be facilitated if the protein is folded as a beta-barrel structure.
authors.affiliation: Unité Mixte de Recherche No 7099, Institut de Biologie Physico-Chimique, CNRS - Université Paris 7-Denis Diderot, 13 rue Pierre et Marie Curie, 75005 Paris, France.
authors.forename: Mohamed N
authors.initials: MN
authors.lastname: Triba
authors.forename: Manuela
authors.initials: M
authors.lastname: Zoonens
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Popot
authors.forename: Philippe F
authors.initials: PF
authors.lastname: Devaux
authors.forename: Dror E
authors.initials: DE
authors.lastname: Warschawski
mesh_terms: D053000:Analytic Sample Preparation Methods; D016880:Anisotropy; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000528:radiation effects / Q000648:ultrastructure; D002942:Circular Dichroism; D004574:Electromagnetic Fields; D005994:Glycerophosphates / Q000737:chemistry / Q000528:radiation effects; D008051:Lipid Bilayers / Q000737:chemistry* / Q000528:radiation effects; D008823:Micelles; D019906:Nuclear Magnetic Resonance, Biomolecular; D010759:Phosphorus Isotopes; D011487:Protein Conformation / Q000528:radiation effects; D020673:Protein Renaturation; D017434:Protein Structure, Tertiary / Q000528:radiation effects; D012975:Sodium Isotopes
chemical_list: D001425:Bacterial Outer Membrane Proteins; D005994:Glycerophosphates; D008051:Lipid Bilayers; D008823:Micelles; D010759:Phosphorus Isotopes; D012975:Sodium Isotopes; C078167:OMPA outer membrane proteins