title: Steroid-based facial amphiphiles for stabilization and crystallization of membrane proteins.
abstract: Amphiphile selection is a critical step for structural studies of membrane proteins (MPs). We have developed a family of steroid-based facial amphiphiles (FAs) that are structurally distinct from conventional detergents and previously developed FAs. The unique FAs stabilize MPs and form relatively small protein-detergent complexes (PDCs), a property considered favorable for MP crystallization. We attempted to crystallize several MPs belonging to different protein families, including the human gap junction channel protein connexin 26, the ATP binding cassette transporter MsbA, the seven-transmembrane G protein-coupled receptor-like bacteriorhodopsin, and cytochrome P450s (peripheral MPs). Using FAs alone or mixed with other detergents or lipids, we obtained 3D crystals of the above proteins suitable for X-ray crystallographic analysis. The fact that FAs enhance MP crystallizability compared with traditional detergents can be attributed to several properties, including increased protein stability, formation of small PDCs, decreased PDC surface flexibility, and potential to mediate crystal lattice contacts.
authors.affiliation: Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Sung Chang
authors.initials: SC
authors.lastname: Lee
authors.forename: Brad C
authors.initials: BC
authors.lastname: Bennett
authors.forename: Wen-Xu
authors.initials: WX
authors.lastname: Hong
authors.forename: Yu
authors.initials: Y
authors.lastname: Fu
authors.forename: Kent A
authors.initials: KA
authors.lastname: Baker
authors.forename: Julien
authors.initials: J
authors.lastname: Marcoux
authors.forename: Carol V
authors.initials: CV
authors.lastname: Robinson
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Ward
authors.forename: James R
authors.initials: JR
authors.lastname: Halpert
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Stevens
authors.forename: Charles David
authors.initials: CD
authors.lastname: Stout
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Yeager
authors.forename: Qinghai
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D018360:Crystallography, X-Ray / Q000379:methods*; D017629:Gap Junctions / Q000737:chemistry*; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry*; D055550:Protein Stability; D013256:Steroids / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D008565:Membrane Proteins; D013256:Steroids; D013501:Surface-Active Agents