首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Identification of the molecular mechanisms by which the diterpenoid salvinorin A binds to kappa-opioid receptors
Authors:Yan Feng  Mosier Philip D  Westkaemper Richard B  Stewart Jeremy  Zjawiony Jordan K  Vortherms Timothy A  Sheffler Douglas J  Roth Bryan L
Institution:Department of Biochemistry, Case Western Reserve University Medical School, Cleveland, Ohio 44106, USA.
Abstract:Salvinorin A is a naturally occurring hallucinogenic diterpenoid from the plant Salvia divinorumthat selectively and potently activates kappa-opioid receptors (KORs). Salvinorin A is unique in that it is the only known lipid-like molecule that selectively and potently activates a G-protein coupled receptor (GPCR), which has as its endogenous agonist a peptide; salvinorin A is also the only known non-nitrogenous opioid receptor agonist. In this paper, we identify key residues in KORs responsible for the high binding affinity and agonist efficacy of salvinorin A. Surprisingly, we discovered that salvinorin A was stabilized in the binding pocket by interactions with tyrosine residues in helix 7 (Tyr313 and Tyr320) and helix 2 (Tyr119). Intriguingly, activation of KORs by salvinorin A required interactions with the helix 7 tyrosines Tyr312, Tyr313, and Tyr320 and with Tyr139 in helix 3. In contrast, the prototypical nitrogenous KOR agonist U69593 and the endogenous peptidergic agonist dynorphin A (1-13) showed differential requirements for these three residues for binding and activation. We also employed a novel approach, whereby we examined the effects of cysteine-substitution mutagenesis on the binding of salvinorin A and an analogue with a free sulfhydryl group, 2-thiosalvinorin B. We discovered that residues predicted to be in close proximity, especially Tyr313, to the free thiol of 2-thiosalvinorin B when mutated to Cys showed enhanced affinity for 2-thiosalvinorin B. When these findings are taken together, they imply that the diterpenoid salvinorin A utilizes unique residues within a commonly shared binding pocket to selectively activate KORs.
Keywords:
本文献已被 PubMed 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号