Dataset Information

A high-resolution description of ?1-adrenergic receptor functional dynamics and allosteric coupling from backbone NMR.

ABSTRACT: Signal transmission and regulation of G-protein-coupled receptors (GPCRs) by extra- and intracellular ligands occurs via modulation of complex conformational equilibria, but their exact kinetic details and underlying atomic mechanisms are unknown. Here we quantified these dynamic equilibria in the ?1-adrenergic receptor in its apo form and seven ligand complexes using 1H/15N NMR spectroscopy. We observe three major exchanging conformations: an inactive conformation (Ci), a preactive conformation (Cp) and an active conformation (Ca), which becomes fully populated in a ternary complex with a G protein mimicking nanobody. The Ci ? Cp exchange occurs on the microsecond scale, the Cp ? Ca exchange is slower than ~5 ms and only occurs in the presence of two highly conserved tyrosines (Y5.58, Y7.53), which stabilize the active conformation of TM6. The Cp?Ca chemical shift changes indicate a pivoting motion of the entire TM6 that couples the effector site to the orthosteric ligand pocket.

SUBMITTER: Grahl A

PROVIDER: S-EPMC7200737 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A high-resolution description of β1-adrenergic receptor functional dynamics and allosteric coupling from backbone NMR.

Grahl Anne A Abiko Layara Akemi LA Isogai Shin S Sharpe Timothy T Grzesiek Stephan S

Nature communications 20200505 1

Signal transmission and regulation of G-protein-coupled receptors (GPCRs) by extra- and intracellular ligands occurs via modulation of complex conformational equilibria, but their exact kinetic details and underlying atomic mechanisms are unknown. Here we quantified these dynamic equilibria in the β1-adrenergic receptor in its apo form and seven ligand complexes using 1H/15N NMR spectroscopy. We observe three major exchanging conformations: an inactive conformati ...[more]

PMID: 32371991

Similar Datasets

Project description:We used a simple experimental approach to clarify some contradictory predictions of the collision coupling and equilibrium models (e.g. ternary complex, two-state ternary complex or quinternary complex), which describe G-protein-mediated beta-adrenergic receptor signalling in essentially different manners. Analysis of the steady-state coupling of beta-adrenoceptors to adenylate cyclase in turkey erythrocyte membranes showed that: (1) in the absence of an agonist, Gpp(NH)p (a hydrolysis-resistant analogue of GTP) can activate adenylate cyclase very slowly; (2) this activity reaches a steady state in approx. 5 h, the extent of activity depending on the concentration of the nucleotide; (3) isoprenaline-activated steady-state adenylate cyclase can be inactivated by propranolol (a competitive antagonist that relaxes the receptor activation), in the presence of Gpp(NH)p (which provides a virtual absence of GTPase) and millimolar concentrations of Mg2+ (the rate of this inactivation is relatively fast); (4) increasing the concentration of Gpp(NH)p can saturate the steady-state activity of adenylate cyclase. The saturated enzyme activity was lower than that induced by isoprenaline under the same conditions. This additional agonist-induced activation was reversible. In the light of these results, we conclude that agonist can also activate the guanine nucleotide-saturated system in the absence of GTPase by a mechanism other than guanine nucleotide exchange. We explain these phenomena in the framework of a quinternary complex model as an agonist-induced and receptor-mediated dissociation of guanine nucleotide-saturated residual heterotrimer, the equilibrium concentration of which is not necessarily zero. These results, which suggest a continuous interaction between receptor and G-protein, can hardly be accommodated by the collision coupling model that was originally suggested for the present experimental system and then applied to many other G-protein systems. Therefore we attempt to unify the equilibrium and collision coupling approaches to provide a consistent theoretical basis for the G-protein-mediated beta-adrenergic receptor signalling in turkey erythrocyte membranes.

Dataset Information

A high-resolution description of ?1-adrenergic receptor functional dynamics and allosteric coupling from backbone NMR.

Publications

A high-resolution description of β<sub>1</sub>-adrenergic receptor functional dynamics and allosteric coupling from backbone NMR.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets