title: Activation and allosteric modulation of a muscarinic acetylcholine receptor.
abstract: Despite recent advances in crystallography and the availability of G-protein-coupled receptor (GPCR) structures, little is known about the mechanism of their activation process, as only the β2 adrenergic receptor (β2AR) and rhodopsin have been crystallized in fully active conformations. Here we report the structure of an agonist-bound, active state of the human M2 muscarinic acetylcholine receptor stabilized by a G-protein mimetic camelid antibody fragment isolated by conformational selection using yeast surface display. In addition to the expected changes in the intracellular surface, the structure reveals larger conformational changes in the extracellular region and orthosteric binding site than observed in the active states of the β2AR and rhodopsin. We also report the structure of the M2 receptor simultaneously bound to the orthosteric agonist iperoxo and the positive allosteric modulator LY2119620. This structure reveals that LY2119620 recognizes a largely pre-formed binding site in the extracellular vestibule of the iperoxo-bound receptor, inducing a slight contraction of this outer binding pocket. These structures offer important insights into the activation mechanism and allosteric modulation of muscarinic receptors.
authors.affiliation: 1] Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305, USA [2].
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Kruse
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Ring
authors.forename: Aashish
authors.initials: A
authors.lastname: Manglik
authors.forename: Jianxin
authors.initials: J
authors.lastname: Hu
authors.forename: Kelly
authors.initials: K
authors.lastname: Hu
authors.forename: Katrin
authors.initials: K
authors.lastname: Eitel
authors.forename: Harald
authors.initials: H
authors.lastname: Hübner
authors.forename: Els
authors.initials: E
authors.lastname: Pardon
authors.forename: Celine
authors.initials: C
authors.lastname: Valant
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Sexton
authors.forename: Arthur
authors.initials: A
authors.lastname: Christopoulos
authors.forename: Christian C
authors.initials: CC
authors.lastname: Felder
authors.forename: Peter
authors.initials: P
authors.lastname: Gmeiner
authors.forename: Jan
authors.initials: J
authors.lastname: Steyaert
authors.forename: William I
authors.initials: WI
authors.lastname: Weis
authors.forename: K Christopher
authors.initials: KC
authors.lastname: Garcia
authors.forename: Jürgen
authors.initials: J
authors.lastname: Wess
authors.forename: Brian K
authors.initials: BK
authors.lastname: Kobilka
mesh_terms: D000494:Allosteric Regulation; D001665:Binding Sites; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D007555:Isoxazoles / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D007555:Isoxazoles; D000644:Quaternary Ammonium Compounds; D011976:Receptors, Muscarinic; C000591650:iperoxo