title: Toward rational design of protein detergent complexes: determinants of mixed micelles that are critical for the in vitro stabilization of a G-protein coupled receptor.
abstract: Although reconstitution of membrane proteins within protein detergent complexes is often used to enable their structural or biophysical characterization, it is unclear how one should rationally choose the appropriate micellar environment to preserve native protein folding. Here, we investigated model mixed micelles consisting of a nonionic glucosylated alkane surfactant from the maltoside and thiomaltoside families, bile salt surfactant, and the steryl derivative cholesteryl hemisuccinate. We correlated several key attributes of these micelles with the in vitro ligand-binding activity of hA(2)aR in these systems. Through small-angle neutron scattering and radioligand-binding analysis, we found several key aspects of mixed micellar systems that preserve the activity of hA(2)aR, including a critical amount of cholesteryl hemisuccinate per micelle, and an optimal hydrophobic thickness of the micelle that is analogous to the thickness of native mammalian bilayers. These features are closely linked to the headgroup chemistry of the surfactant and the hydrocarbon chain length, which influence both the morphology and composition of resulting micelles. This study should serve as a general guide for selecting the appropriate mixed surfactant systems to stabilize membrane proteins for biophysical analysis.
authors: Department of Chemical Engineering, University of Delaware, Newark, Delaware, USA.
authors: Michelle A
authors: MA
authors: O'Malley
authors: Matthew E
authors: ME
authors: Helgeson
authors: Norman J
authors: NJ
authors: Wagner
authors: Anne S
authors: AS
authors: Robinson
mesh_terms: D002788:Cholesterol Esters / Q000737:chemistry; D003902:Detergents / Q000737:chemistry* / Q000378:metabolism; D015195:Drug Design; D006801:Humans; D008823:Micelles; D033363:Neutron Diffraction; D011487:Protein Conformation; D055550:Protein Stability; D043705:Receptor, Adenosine A2A / Q000737:chemistry* / Q000378:metabolism; D053838:Scattering, Small Angle
chemical_list: D002788:Cholesterol Esters; D003902:Detergents; D008823:Micelles; D043705:Receptor, Adenosine A2A; C013440:cholesteryl succinate