Title | Structural flexibility of the G alpha s alpha-helical domain in the beta2-adrenoceptor Gs complex. |
Publication Type | Journal Article |
Year of Publication | 2011 |
Authors | Westfield, G. H., S. G. F. Rasmussen, M. Su, S. Dutta, B. T. Devree, K. Young Chung, D. Calinski, G. Velez-Ruiz, A. N. Oleskie, E. Pardon, P. Seok Chae, T. Liu, S. Li, V. L. Woods, J. Steyaert, B. K. Kobilka, R. K. Sunahara, and G. Skiniotis |
Journal | Proc Natl Acad Sci U S A |
Volume | 108 |
Issue | 38 |
Pagination | 16086-91 |
Date Published | 2011 Sep 20 |
ISSN | 1091-6490 |
Keywords | Animals, Crystallization, Crystallography, X-Ray, GTP-Binding Protein alpha Subunits, Gs, Guanosine 5'-O-(3-Thiotriphosphate), Guanosine Diphosphate, Guanosine Triphosphate, Microscopy, Electron, Models, Molecular, Protein Binding, Protein Conformation, Protein Structure, Secondary, Protein Structure, Tertiary, Receptors, Adrenergic, beta-2 |
Abstract | The active-state complex between an agonist-bound receptor and a guanine nucleotide-free G protein represents the fundamental signaling assembly for the majority of hormone and neurotransmitter signaling. We applied single-particle electron microscopy (EM) analysis to examine the architecture of agonist-occupied β(2)-adrenoceptor (β(2)AR) in complex with the heterotrimeric G protein Gs (Gαsβγ). EM 2D averages and 3D reconstructions of the detergent-solubilized complex reveal an overall architecture that is in very good agreement with the crystal structure of the active-state ternary complex. Strikingly however, the α-helical domain of Gαs appears highly flexible in the absence of nucleotide. In contrast, the presence of the pyrophosphate mimic foscarnet (phosphonoformate), and also the presence of GDP, favor the stabilization of the α-helical domain on the Ras-like domain of Gαs. Molecular modeling of the α-helical domain in the 3D EM maps suggests that in its stabilized form it assumes a conformation reminiscent to the one observed in the crystal structure of Gαs-GTPγS. These data argue that the α-helical domain undergoes a nucleotide-dependent transition from a flexible to a conformationally stabilized state. |
DOI | 10.1073/pnas.1113645108 |
Alternate Journal | Proc. Natl. Acad. Sci. U.S.A. |
PubMed ID | 21914848 |
PubMed Central ID | PMC3179071 |
Grant List | AI076961 / AI / NIAID NIH HHS / United States AI08192 / AI / NIAID NIH HHS / United States AI2008031 / AI / NIAID NIH HHS / United States CA118595 / CA / NCI NIH HHS / United States GM008270 / GM / NIGMS NIH HHS / United States GM066170 / GM / NIGMS NIH HHS / United States GM093325 / GM / NIGMS NIH HHS / United States GM20501 / GM / NIGMS NIH HHS / United States P60DK-20572 / DK / NIDDK NIH HHS / United States R01 GM020501-36 / GM / NIGMS NIH HHS / United States R01 GM068603 / GM / NIGMS NIH HHS / United States R01-DK090165 / DK / NIDDK NIH HHS / United States R01-GM068603 / GM / NIGMS NIH HHS / United States R01-GM083118 / GM / NIGMS NIH HHS / United States R01-NS28471 / NS / NINDS NIH HHS / United States RR029388 / RR / NCRR NIH HHS / United States |
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