作用钾通道KCNQ1特异性多肽的分子设计及功能机制研究

KCNQ1 channel has been proved to associate with many physiological and pathological processes. However, the structural and functional research of KCNQ1 channel progressed slowly for the lacking of potent peptide inhibitors as probes. Project applicant has started to screen KCNQ1 channel-speicific peptides from scorpion venom since 2007. Many experimental data have showed that KCNQ1 channel was not sensitive to classcial basic scorpion toxins, but novel acidic scorpion toxins have weak activities towards KCNQ1 channel (with Kd of about 11μM, PLoS ONE,2012), and near-neutral scorpion toxins have better acitivities(with Kd of about 1-4.6μM). On the base of these studies, we will chose near-neutral scorpion toxins as template in this project, and focus our attentions on the molecular design with the help of molecular dymamics simuation and laws of toxin-potassium channel interaction. Electrophysiological experiments will be used to test the activities of a series of designed pepitdes. Finally, potent inhibitors spicific for KCNQ1channel will be selected. Using potent pepitdes as probes, we will further research the structure-function relationship of KCNQ1 channel interacting with peptide inhibitors and explain the molecualr mechinism of peptide recognizing KCNQ1 channel. Our research will lay the theoretical foundation and provide the scientific basis on the sructure and function research of KCNQ1 channel with peptide probes as tools.

KCNQ1钾通道与众多生理病理过程密切相关。因缺乏特异性多肽调节剂，其结构功能研究进展缓慢。项目申请人自2007年开始从事作用钾通道KCNQ1特异性多肽的筛选设计研究，大量实验发现了KCNQ1钾通道对经典碱性蝎毒素多肽不敏感，对系列新型酸性蝎毒素多肽弱敏感（Kd值约为11μM，相关结果发表在PLoS ONE,2012），对近中性多肽较敏感（Kd值约为1-4.6μM）。据此，本项目拟以近中性多肽为模板，运用蝎毒素多肽-钾通道相互作用的生物学信息和计算机辅助设计的策略，合理设计系列潜在作用钾通道KCNQ1的多肽调节剂，通过电生理实验鉴定特异性多肽。在此基础上，深入研究钾通道KCNQ1与特异性多肽相互作用的分子机制，阐明其对不同的毒素多肽敏感和耐受的结构基础，为以特异性多肽作为新型"分子探针"研究KCNQ1钾通道结构功能及生理病理过程中的作用奠定理论基础，提供科学依据。

KCNQ1 钾通道与众多生理病理过程密切相关，但是缺乏特异性多肽调节剂，严重影响了KCNQ1通道结构和功能的基础研究和基于KCNQ1钾通道的药物开发应用研究进展。本项目首先以经典的CSα/β结构模体多肽BmKTX及其类似物为模板，以近中性多肽主要突破口，运用蝎毒素多肽-钾通道相互作用的生物学信息和计算机辅助设计的策略，得到作用钾通道KCNQ1 的两个新多肽调节剂MT2和MT2-2，并进一步研究了多肽和钾通道相互作用的分子机制，初步阐明了钾通道和多肽相互作用的共性和个性规律；在此基础上，我们结合蝎毒素分子多肽的结构和功能多样性基础，筛选得到一个新型Ascaris-type结构模体多肽，为靶向KCNQ1多肽的设计开发提供了新思路；最后，我们探索了KCNQ1钾通道对不同的毒素多肽敏感和耐受的结构基础，为进一步优化改造作用KCNQ1 钾通道的多肽分子奠定了理论基础。