Publication Date:
2012-02-24
Description:
Acetylcholine, the first neurotransmitter to be identified, exerts many of its physiological actions via activation of a family of G-protein-coupled receptors (GPCRs) known as muscarinic acetylcholine receptors (mAChRs). Although the five mAChR subtypes (M1-M5) share a high degree of sequence homology, they show pronounced differences in G-protein coupling preference and the physiological responses they mediate. Unfortunately, despite decades of effort, no therapeutic agents endowed with clear mAChR subtype selectivity have been developed to exploit these differences. We describe here the structure of the G(q/11)-coupled M3 mAChR ('M3 receptor', from rat) bound to the bronchodilator drug tiotropium and identify the binding mode for this clinically important drug. This structure, together with that of the G(i/o)-coupled M2 receptor, offers possibilities for the design of mAChR subtype-selective ligands. Importantly, the M3 receptor structure allows a structural comparison between two members of a mammalian GPCR subfamily displaying different G-protein coupling selectivities. Furthermore, molecular dynamics simulations suggest that tiotropium binds transiently to an allosteric site en route to the binding pocket of both receptors. These simulations offer a structural view of an allosteric binding mode for an orthosteric GPCR ligand and provide additional opportunities for the design of ligands with different affinities or binding kinetics for different mAChR subtypes. Our findings not only offer insights into the structure and function of one of the most important GPCR families, but may also facilitate the design of improved therapeutics targeting these critical receptors.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3529910/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3529910/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kruse, Andrew C -- Hu, Jianxin -- Pan, Albert C -- Arlow, Daniel H -- Rosenbaum, Daniel M -- Rosemond, Erica -- Green, Hillary F -- Liu, Tong -- Chae, Pil Seok -- Dror, Ron O -- Shaw, David E -- Weis, William I -- Wess, Jurgen -- Kobilka, Brian K -- GM56169/GM/NIGMS NIH HHS/ -- NS028471/NS/NINDS NIH HHS/ -- R01 GM083118/GM/NIGMS NIH HHS/ -- R01 NS028471/NS/NINDS NIH HHS/ -- Intramural NIH HHS/ -- England -- Nature. 2012 Feb 22;482(7386):552-6. doi: 10.1038/nature10867.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, California 94305, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22358844" target="_blank"〉PubMed〈/a〉
Keywords:
Acetylcholine/chemistry/metabolism
;
Allosteric Site
;
Animals
;
COS Cells
;
Crystallization
;
Crystallography, X-Ray
;
Kinetics
;
Ligands
;
Models, Molecular
;
Molecular Dynamics Simulation
;
Radioligand Assay
;
Rats
;
Receptor, Muscarinic M3/*chemistry/*metabolism
;
Scopolamine Derivatives/chemistry/metabolism
;
Substrate Specificity
;
Tiotropium Bromide
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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