期刊
NATURE
卷 477, 期 7366, 页码 611-U143出版社
NATURE PUBLISHING GROUP
DOI: 10.1038/nature10488
关键词
-
资金
- American Lung Association [RT-166882-N]
- Lundbeck Foundation
- National Institute of General Medical Sciences (NIGMS) [GM008270, GM083118, GM068603]
- National Institute of Neural Disorders and Stroke [NS28471]
- NHLBI [HL071078]
- Mather Charitable Foundation
- Michigan Diabetes Research and Training Center
- National Institute of Diabetes and Digestive and Kidney Diseases [P60DK-20572]
- University of Michigan
- NIH [AI076961, AI081982, AI2008031, CA118595, GM20501, GM066170, GM093325, RR029388]
- Lundbeck Foundation [R37-2009-3457] Funding Source: researchfish
G protein-coupled receptors represent the largest family of membrane receptors(1) that instigate signalling through nucleotide exchange on heterotrimeric G proteins. Nucleotide exchange, or more precisely, GDP dissociation from the G protein alpha-subunit, is the key step towards G protein activation and initiation of downstream signalling cascades. Despite a wealth of biochemical and biophysical studies on inactive and active conformations of several heterotrimeric G proteins, the molecular underpinnings of G protein activation remain elusive. To characterize this mechanism, we applied peptide amide hydrogen-deuterium exchange mass spectrometry to probe changes in the structure of the heterotrimeric bovine G protein, Gs (the stimulatory G protein for adenylyl cyclase) on formation of a complex with agonist-bound human beta(2) adrenergic receptor (beta(2)AR). Here we report structural links between the receptor-binding surface and the nucleotide-binding pocket of Gs that undergo higher levels of hydrogen-deuterium exchange than would be predicted from the crystal structure of the beta(2)AR-Gs complex. Together with X-ray crystallographic and electron microscopic data of the beta(2)AR-Gs complex (from refs 2, 3), we provide a rationale for a mechanism of nucleotide exchange, whereby the receptor perturbs the structure of the amino-terminal region of the alpha-subunit of Gs and consequently alters the 'P-loop' that binds the beta-phosphate in GDP. As with the Ras family of small-molecular-weight G proteins, P-loop stabilization and beta-phosphate coordination are key determinants of GDP (and GTP) binding affinity.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据