title: How Do Short Chain Nonionic Detergents Destabilize G-Protein-Coupled Receptors?
abstract: Stability of detergent-solubilized G-protein-coupled receptors (GPCRs) is crucial for their purification in a biologically relevant state, and it is well-known that short chain detergents such as octylglucoside are more denaturing than long chain detergents such as dodecylmaltoside. However, the molecular basis for this phenomenon is poorly understood. To gain insights into the mechanism of detergent destabilization of GPCRs, we used atomistic molecular dynamics simulations of thermostabilized adenosine receptor (A2AR) mutants embedded in either a lipid bilayer or detergent micelles of alkylmaltosides and alkylglucosides. A2AR mutants in dodecylmaltoside or phospholipid showed low flexibility and good interhelical packing. In contrast, A2AR mutants in either octylglucoside or nonylglucoside showed decreased α-helicity in transmembrane regions, decreased α-helical packing, and the interpenetration of detergent molecules between transmembrane α-helices. This was not observed in octylglucoside containing phospholipid. Cholesteryl hemisuccinate in dodecylmaltoside increased the energetic stability of the receptor by wedging into crevices on the hydrophobic surface of A2AR, increasing packing interactions within the receptor and stiffening the detergent micelle. The data suggest a three-stage process for the initial events in the destabilization of GPCRs by octylglucoside: (i) highly mobile detergent molecules form small micelles around the receptor; (ii) loss of α-helicity and decreased interhelical packing interactions in transmembrane regions are promoted by increased receptor thermal motion; (iii) transient separation of transmembrane helices allowed penetration of detergent molecules into the core of the receptor. The relative hydration of the headgroup and alkyl chain correlates with detergent harshness and suggests new avenues to develop milder versions of octylglucoside for receptor crystallization.
authors: Department of Molecular Immunology, Beckman Research Institute of the City of Hope , 1500 E. Duarte Road, Duarte, California 91010, United States.
authors: Sangbae
authors: S
authors: Lee
authors: Department of Molecular Immunology, Beckman Research Institute of the City of Hope , 1500 E. Duarte Road, Duarte, California 91010, United States.
authors: Allen
authors: A
authors: Mao
authors: Department of Molecular Immunology, Beckman Research Institute of the City of Hope , 1500 E. Duarte Road, Duarte, California 91010, United States.
authors: Supriyo
authors: S
authors: Bhattacharya
authors: Heptares Therapeutics Ltd , BioPark, Broadwater Road, Welwyn Garden City AL7 3AX, U.K.
authors: Nathan
authors: N
authors: Robertson
authors: Membrane Protein Structure Function Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Department of Health and Human Services , Rockville, Maryland 20852, United States.
authors: Reinhard
authors: R
authors: Grisshammer
authors: MRC Laboratory of Molecular Biology , Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, U.K.
authors: Christopher G
authors: CG
authors: Tate
authors: Department of Molecular Immunology, Beckman Research Institute of the City of Hope , 1500 E. Duarte Road, Duarte, California 91010, United States.
authors: Nagarajan
authors: N
authors: Vaidehi
mesh_terms: D003902:Detergents / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D009154:Mutation; D055550:Protein Stability; D043705:Receptor, Adenosine A2A / Q000737:chemistry* / Q000235:genetics
chemical_list: D003902:Detergents; D043705:Receptor, Adenosine A2A