雷氏大疣蛛毒素RNTX-A28抑制电压门控质子通道的分子机制研究

电压门控质子通道在先天免疫、精子成熟及癌细胞增殖侵袭等过程中具有重要作用，是一个潜在的药物靶点。由于至今仅有Zn2+和胍基衍生物两类抑制剂，限制了该通道的药理学研究进展。为了鉴定质子通道抑制剂，对本室储存的多肽毒素库进行了大规模筛选，获得了首个高活性和高专一性的多肽抑制剂RNTX-A28。相比于上述两类抑制剂，该多肽有完全不同的分子结构和作用模式，是一个新型的质子通道抑制剂。本项目以阐明专一性质子通道抑制剂RNTX-A28的作用机制为目标，利用膜片钳、2D-1HNMR、基因突变等技术解析该多肽抑制质子通道的作用模式、相互作用的结构基础，并初步探讨它对乳腺癌细胞增殖及侵袭能力的影响。通过对该多肽作用机制的深入解析，将为质子通道结构与功能、药理学等研究提供一个重要分子工具及潜在的药物先导分子；同时，还将发现质子通道上一个新的药物结合位点，扩展和深化抑制剂与质子通道相互作用的理解。

Despite a vital role of voltage-gated hydrogen channels (HV1) in the innate immunology, sperm maturation, as well as in the proliferation and invasion of cancer cells, its pharmacology is largely unexplored due to the scarcity of modifiers. Up to date, only Zn2+ and guanidine derivatives were reported to be effective HV1 blockers. Our previous study aimed to identify HV1 blockers from peptide toxins. About 600 RP-HPLC fractions from several venoms were screened and RNTX-A28 from the venom of spider Macrothele raveni was confirmed to be an antagonist of HV1 with high affinity (IC50 ≈ 1 µM) and specificity. To our knowledge, this is the first report of a peptide toxin acting on HV1. The structure and the interaction mode of RNTX-A28 acting on HV1 were completely different from those of Zn2+ and guanidine derivatives, which indicates the binding site of RNTX-A28 in HV1 is novel. In-depth study aims to uncover the mechanism by which RNTX-A28 interacts with HV1 by patch-clamp, 2D-1HNMR and mutation analysis. Meanwhile, the effect of RNTX-A28 on the proliferation and invasion of MDA-MB231 cells by inhibiting its endogenous proton currents will be explored. In summary, our study provided a useful probe for exploring the structure, function and the pharmacology of HV1. In addition, RNTX-A28 would be a potential drug lead for the development of drugs targeting HV1.