The morphology and composition of cholesterol-rich micellar nanostructures determine transmembrane protein (GPCR) activity.
We examined model mixed micelles consisting of the nonionic surfactant n-dodecyl-β-D-maltoside, 3-(3-cholamidopropyl)-dimethylammoniopropane sulfonate, and the cholesterol derivative cholesteryl hemisuccinate (CHS) to identify micellar properties that are correlated with the in vitro conformational stability and activity of the human adenosine A₂a receptor, a G-protein coupled receptor. Small-angle neutron scattering was used to determine micellar structure and composition as a function of concentration of the various components, and radioligand binding was used as a sensitive probe for receptor activity. Micelles adopted an oblate ellipsoidal morphology and exhibited a reduction in size and change in curvature upon addition of CHS. Our results show a strong correlation between the number of CHS monomers per micelle and the activity of the receptor reconstituted in those micelles. Micelles that yield optimal human adenosine A₂a receptor stability closely mimic the cholesterol composition and thickness of mammalian membranes. Thus, successful reconstitution of the receptor is dependent on both specific lipid-protein interactions and the geometry of the micelle environment.
Michelle A
MA
O'Malley
Matthew E
ME
Helgeson
Norman J
NJ
Wagner
Anne S
AS
Robinson
D002784:Cholesterol / Q000737:chemistry*; D002788:Cholesterol Esters / Q000737:chemistry*; D002793:Cholic Acids / Q000737:chemistry; D005960:Glucosides / Q000737:chemistry*; D006801:Humans; D008565:Membrane Proteins / Q000648:ultrastructure; D008823:Micelles; D008968:Molecular Conformation; D049329:Nanostructures / Q000648:ultrastructure; D021381:Protein Transport / Q000502:physiology*; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry* / Q000378:metabolism*; D053838:Scattering, Small Angle; D013499:Surface Properties
D002788:Cholesterol Esters; D002793:Cholic Acids; D005960:Glucosides; D008565:Membrane Proteins; D008823:Micelles; D043562:Receptors, G-Protein-Coupled; C040358:dodecyl maltoside; D002784:Cholesterol; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate; C013440:cholesteryl succinate
J Biol Chem. 2001 Aug 31;276(35):32403-6
11432878
Prog Lipid Res. 2006 Jul;45(4):295-333
16616960
Biochim Biophys Acta. 2000 Nov 23;1508(1-2):86-111
11090820
Lipids. 2004 Nov;39(11):1101-13
15726825
Science. 2008 Nov 21;322(5905):1211-7
18832607
J Struct Biol. 2007 Aug;159(2):166-78
17591446
Structure. 2009 Dec 9;17(12):1660-1668
20004169
Chembiochem. 2004 Apr 2;5(4):423-6
15185363
Structure. 2008 Jun;16(6):897-905
18547522
Comb Chem High Throughput Screen. 2008 Jul;11(6):439-62
18673272
Biochim Biophys Acta. 2004 Nov 3;1666(1-2):105-17
15519311
Eur J Biochem. 2002 Jan;269(1):82-92
11784301