title: High-resolution structure of a membrane protein transferred from amphipol to a lipidic mesophase.
abstract: Amphipols (APols) have become important tools for the stabilization, folding, and in vitro structural and functional studies of membrane proteins (MPs). Direct crystallization of MPs solubilized in APols would be of high importance for structural biology. However, despite considerable efforts, it is still not clear whether MP/APol complexes can form well-ordered crystals suitable for X-ray crystallography. In the present work, we show that an APol-trapped MP can be crystallized in meso. Bacteriorhodopsin (BR) trapped by APol A8-35 was mixed with a lipidic mesophase, and crystallization was induced by adding a precipitant. The crystals diffract beyond 2 Å. The structure of BR was solved to 2 Å and found to be indistinguishable from previous structures obtained after transfer from detergent solutions. We suggest the proposed protocol of in meso crystallization to be generally applicable to APol-trapped MPs.
authors.affiliation: Univ. Grenoble Alpes, IBS, 38044, Grenoble, France.
authors.forename: V
authors.initials: V
authors.lastname: Polovinkin
authors.forename: I
authors.initials: I
authors.lastname: Gushchin
authors.forename: M
authors.initials: M
authors.lastname: Sintsov
authors.forename: E
authors.initials: E
authors.lastname: Round
authors.forename: T
authors.initials: T
authors.lastname: Balandin
authors.forename: P
authors.initials: P
authors.lastname: Chervakov
authors.forename: V
authors.initials: V
authors.lastname: Shevchenko
authors.forename: P
authors.initials: P
authors.lastname: Utrobin
authors.forename: A
authors.initials: A
authors.lastname: Popov
authors.forename: V
authors.initials: V
authors.lastname: Borshchevskiy
authors.forename: A
authors.initials: A
authors.lastname: Mishin
authors.forename: A
authors.initials: A
authors.lastname: Kuklin
authors.forename: D
authors.initials: D
authors.lastname: Willbold
authors.forename: V
authors.initials: V
authors.lastname: Chupin
authors.forename: J-L
authors.initials: JL
authors.lastname: Popot
authors.forename: V
authors.initials: V
authors.lastname: Gordeliy
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry* / Q000648:ultrastructure*; D003460:Crystallization / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry* / Q000648:ultrastructure; D011108:Polymers / Q000737:chemistry*; D011437:Propylamines / Q000737:chemistry*; D011487:Protein Conformation; D012995:Solubility; D012996:Solutions; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D008565:Membrane Proteins; D011108:Polymers; D011437:Propylamines; D012996:Solutions; D013501:Surface-Active Agents; C499017:amphipol A8-35; D001436:Bacteriorhodopsins