EMD-29991
CryoEM structure of beta-2-adrenergic receptor in complex with GTP-bound Gs heterotrimer (transition intermediate #7 of 20)
EMD-29991
Single-particle3.0 Å
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Map released: 06/03/2024
Last modified: 13/11/2024
Sample Organism:
Homo sapiens
Sample: Complex of beta-2 adrenergic receptor and Gs heterotrimer with GTP
Fitted models: 8gg1 (Avg. Q-score: 0.572)
Raw data: EMPIAR-11856, EMPIAR-11858, EMPIAR-11857
Deposition Authors: Papasergi-Scott MM
,
Skiniotis G
Sample: Complex of beta-2 adrenergic receptor and Gs heterotrimer with GTP
Fitted models: 8gg1 (Avg. Q-score: 0.572)
Raw data: EMPIAR-11856, EMPIAR-11858, EMPIAR-11857
Deposition Authors: Papasergi-Scott MM
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Time-resolved cryo-EM of G-protein activation by a GPCR.
Papasergi-Scott MM
,
Perez-Hernandez G
,
Batebi H
,
Gao Y
,
Eskici G
,
Seven AB
,
Panova O
,
Hilger D
,
Casiraghi M,
He F
,
Maul L,
Gmeiner P
,
Kobilka BK
,
Hildebrand PW
,
Skiniotis G
(2024) Nature , 629 , 1182 - 1191
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(2024) Nature , 629 , 1182 - 1191
Abstract:
G-protein-coupled receptors (GPCRs) activate heterotrimeric G proteins by stimulating guanine nucleotide exchange in the Gα subunit1. To visualize this mechanism, we developed a time-resolved cryo-EM approach that examines the progression of ensembles of pre-steady-state intermediates of a GPCR-G-protein complex. By monitoring the transitions of the stimulatory Gs protein in complex with the β2-adrenergic receptor at short sequential time points after GTP addition, we identified the conformational trajectory underlying G-protein activation and functional dissociation from the receptor. Twenty structures generated from sequential overlapping particle subsets along this trajectory, compared to control structures, provide a high-resolution description of the order of main events driving G-protein activation in response to GTP binding. Structural changes propagate from the nucleotide-binding pocket and extend through the GTPase domain, enacting alterations to Gα switch regions and the α5 helix that weaken the G-protein-receptor interface. Molecular dynamics simulations with late structures in the cryo-EM trajectory support that enhanced ordering of GTP on closure of the α-helical domain against the nucleotide-bound Ras-homology domain correlates with α5 helix destabilization and eventual dissociation of the G protein from the GPCR. These findings also highlight the potential of time-resolved cryo-EM as a tool for mechanistic dissection of GPCR signalling events.
G-protein-coupled receptors (GPCRs) activate heterotrimeric G proteins by stimulating guanine nucleotide exchange in the Gα subunit1. To visualize this mechanism, we developed a time-resolved cryo-EM approach that examines the progression of ensembles of pre-steady-state intermediates of a GPCR-G-protein complex. By monitoring the transitions of the stimulatory Gs protein in complex with the β2-adrenergic receptor at short sequential time points after GTP addition, we identified the conformational trajectory underlying G-protein activation and functional dissociation from the receptor. Twenty structures generated from sequential overlapping particle subsets along this trajectory, compared to control structures, provide a high-resolution description of the order of main events driving G-protein activation in response to GTP binding. Structural changes propagate from the nucleotide-binding pocket and extend through the GTPase domain, enacting alterations to Gα switch regions and the α5 helix that weaken the G-protein-receptor interface. Molecular dynamics simulations with late structures in the cryo-EM trajectory support that enhanced ordering of GTP on closure of the α-helical domain against the nucleotide-bound Ras-homology domain correlates with α5 helix destabilization and eventual dissociation of the G protein from the GPCR. These findings also highlight the potential of time-resolved cryo-EM as a tool for mechanistic dissection of GPCR signalling events.