人类钾离子通HERG的调控蛋白MiRP1的液体核磁共振结构生物学研究

项目名称： 人类钾离子通HERG的调控蛋白MiRP1的液体核磁共振结构生物学研究

项目编号： No.30870489

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 武器工业

项目作者： 田长麟

作者单位： 中国科学技术大学

项目金额： 32万元

中文摘要： MiRP1（Mink Related Protein 1）是由kcne2基因编码的含有123个氨基酸的单次跨膜蛋白。MiRP1蛋白能和许多不同的钾离子通道蛋白（其中主要和人HERG， human ether-a-go-go钾离子通道蛋白）相结合，并调节这些钾离子通道的动力学特性，同时和胃酸分泌具有非常密切的关系。在临床上发现，许多在kcne2基因上的突变是导致先天性和获得性的LQT综合症的主要原因。其中MiRP1及HERG钾离子通道的功能异常并导致后天获得性LQT综合症还是许多新开发的小分子药物导致病人瘁死的主要原因。因此，针对MiRP1及HERG的研究不仅具有非常重要的生理学意义，而且具有非常重要的药物市场意义。目前国际上针对MiRP1的研究非常多，但是主要集中生理学和临床药理学方面，而对于MiRP1的三维结构研究尚未见报道。本项目应用细菌表达体系，高效表达和纯化MiRP1蛋白，并应用去污剂胶束来模拟MiRP1所处的磷脂双分子层环境，应用液体核磁共振方法解析了MiRP1在去污剂胶束中的三维结构,并分析了MiRP1蛋白的动力学特性及初步探索了MiRP1结合并调节KCNQ1的方式。

中文关键词： MiRP1; 离子通道；液体核磁共振；膜蛋白结构；主链动力学

英文摘要： MiRP1 is a membrane protein with single transmembrane helix, and it contains 123 amino acids, encoded by gene kcne2. MiRP1 can associate and modulate gating dynamics and functions of many K+ channel proteins (mainly with human HERG, human ether-a-go-go). MiRP1 is also found to be important in gastric acid secretion. Clinic data indicate that many mutations in kcne2 gene were found to be the major reason in genetic and acquired Long QT syndrome. The malfunction of MiRP1-HERG was very important reason for patient sudden death by small compound drugs, demonstrating physiological and pharmacological importance of MiRP1. Many MiRP1 studies are reported but most of them are focusing on physiology, pathogenic and pharmacology studies, while structural studies and consequent molecular mechanism of MiRP1 were rarely reported. Here，MiRP1 was over-expressed using bacterial expression system. After screening detergent micelles, we have obtained optimized sample condition for MiRP1. Solution NMR data of MiRP1 in detergent micelles were obtained for further backbone assignment and further structural determination. Three dimensional struture and backbone dynamics of MiRP1 in detergent micelles were analyzed. The structural and relaxation data provide hints on how the MiRP1 associate with and modulate channel conductance properties of KCNQ1.

英文关键词： MiRP1; ion channel; solution NMR; membrane protein structure； backbone dynamics