类胰岛素肽7与其G-蛋白偶联受体RXFP3相互作用的分子机制

项目名称： 类胰岛素肽7与其G-蛋白偶联受体RXFP3相互作用的分子机制

项目编号： No.31270824

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 生物科学

项目作者： 郭占云

作者单位： 同济大学

项目金额： 80万元

中文摘要： 类胰岛素肽7（INSL7，亦称为松弛素3）是2002年才发现的一个属于胰岛素超家族的神经肽。它主要在脑中表达，通过激活G-蛋白偶联受体RXFP3参与了食欲、压力、应激、感知等相关生理功能调控，但目前对两者相互作用的细节还知之甚少。鉴于此，我们拟从配基和受体两个互补的角度研究INSL7与RXFP3相互作用的分子机制。从受体角度，先利用易于制备的光活化INSL7 B-链类似物通过光照交联的方法定位RXFP3中配基结合口袋，再通过丙氨酸扫描确定配基结合口袋中参与INSL7结合的关键残基。从配基角度，利用稳定同位素标记的配基及重组表达的受体通过NMR方法解析RXFP3结合状态下INSL7的三维结构，确定参与受体结合的关键残基及受体结合诱导的构象变化。阐明两者相互作用的分子机制将为设计对RXFP3更专一的激动性或拮抗性INSL7类似物提供理论依据，对研究其它类胰岛素肽与受体的相互作用也有借鉴意义。

中文关键词： 类胰岛素肽7；松弛素3；松弛素家族多肽受体3；G蛋白偶联受体；相互作用

英文摘要： Insulin-like peptide 7 (INSL7), also known as relaxin-3, is a new member of the insulin superfamily identified as a neuropeptide in 2002. It is predominantly expressed in the brain and involved in the regulation of food intake, stress response, arousal and sensory by activating its cognate G-protein coupled receptor RXFP3, but their interaction details are largely remained unknown so far. Therefore, we proposed to study their interaction mechanism from the views of both the ligand and the receptor. For study of the receptor, we plan to first disclose the ligand-binding pocket of RXFP3 through photoaffinity labeling by using the easily prepared photoactivatable INSL7 B-chain analogues, and subsequently identify the key ligand-binding residues in the ligand-binding pocket of RXFP3 by alanine-scanning mutagenesis. For study of the ligand, we plan to solve the receptor-bound three-dimensional structure of INSL7 through NMR technology by using the stable isotope-labeled ligand and the recombinant receptor, thus revealing the receptor-binding residues and the receptor-binding induced conformational change of INSL7. Demonstrating the molecular mechanism of the ligand-receptor interaction will provide new valuable insights for designing novel RXFP3-specific agonistic or antagonistic INSL7 analogues as well as the inter

英文关键词： INSL7；Relaxin-3；RXFP3；GPCR；Interaction