TY - JOUR

T1 - Mechanistic insights into G-protein coupling with an agonist-bound G-protein-coupled receptor

AU - Batebi, Hossein

AU - Pérez-Hernández, Guillermo

AU - Rahman, Sabrina N.

AU - Lan, Baoliang

AU - Kamprad, Antje

AU - Shi, Mingyu

AU - Speck, David

AU - Tiemann, Johanna K.S.

AU - Guixà-González, Ramon

AU - Reinhardt, Franziska

AU - Stadler, Peter F.

AU - Papasergi-Scott, Makaía M.

AU - Skiniotis, Georgios

AU - Scheerer, Patrick

AU - Kobilka, Brian K.

AU - Mathiesen, Jesper M.

AU - Liu, Xiangyu

AU - Hildebrand, Peter W.

N1 - Publisher Copyright: © The Author(s), under exclusive licence to Springer Nature America, Inc. 2024.

PY - 2024

Y1 - 2024

N2 - G-protein-coupled receptors (GPCRs) activate heterotrimeric G proteins by promoting guanine nucleotide exchange. Here, we investigate the coupling of G proteins with GPCRs and describe the events that ultimately lead to the ejection of GDP from its binding pocket in the Gα subunit, the rate-limiting step during G-protein activation. Using molecular dynamics simulations, we investigate the temporal progression of structural rearrangements of GDP-bound Gs protein (Gs·GDP; hereafter GsGDP) upon coupling to the β2-adrenergic receptor (β2AR) in atomic detail. The binding of GsGDP to the β2AR is followed by long-range allosteric effects that significantly reduce the energy needed for GDP release: the opening of α1-αF helices, the displacement of the αG helix and the opening of the α-helical domain. Signal propagation to the Gs occurs through an extended receptor interface, including a lysine-rich motif at the intracellular end of a kinked transmembrane helix 6, which was confirmed by site-directed mutagenesis and functional assays. From this β2AR–GsGDP intermediate, Gs undergoes an in-plane rotation along the receptor axis to approach the β2AR–Gsempty state. The simulations shed light on how the structural elements at the receptor–G-protein interface may interact to transmit the signal over 30 Å to the nucleotide-binding site. Our analysis extends the current limited view of nucleotide-free snapshots to include additional states and structural features responsible for signaling and G-protein coupling specificity.

AB - G-protein-coupled receptors (GPCRs) activate heterotrimeric G proteins by promoting guanine nucleotide exchange. Here, we investigate the coupling of G proteins with GPCRs and describe the events that ultimately lead to the ejection of GDP from its binding pocket in the Gα subunit, the rate-limiting step during G-protein activation. Using molecular dynamics simulations, we investigate the temporal progression of structural rearrangements of GDP-bound Gs protein (Gs·GDP; hereafter GsGDP) upon coupling to the β2-adrenergic receptor (β2AR) in atomic detail. The binding of GsGDP to the β2AR is followed by long-range allosteric effects that significantly reduce the energy needed for GDP release: the opening of α1-αF helices, the displacement of the αG helix and the opening of the α-helical domain. Signal propagation to the Gs occurs through an extended receptor interface, including a lysine-rich motif at the intracellular end of a kinked transmembrane helix 6, which was confirmed by site-directed mutagenesis and functional assays. From this β2AR–GsGDP intermediate, Gs undergoes an in-plane rotation along the receptor axis to approach the β2AR–Gsempty state. The simulations shed light on how the structural elements at the receptor–G-protein interface may interact to transmit the signal over 30 Å to the nucleotide-binding site. Our analysis extends the current limited view of nucleotide-free snapshots to include additional states and structural features responsible for signaling and G-protein coupling specificity.

U2 - 10.1038/s41594-024-01334-2

DO - 10.1038/s41594-024-01334-2

M3 - Journal article

C2 - 38867113

AN - SCOPUS:85195646770

JO - Nature Structural and Molecular Biology

JF - Nature Structural and Molecular Biology

SN - 1545-9993

ER -