蜘蛛多肽毒素HpTx-V增强质子通道OTOP1电流的分子机制研究

OTOP1通道是2018年鉴定的一个新质子通道，介导小鼠舌酸感受细胞上的内向质子电流，作为该领域的一个重大突破，对探究哺乳动物酸感受行为有重要意义，其相关研究获得密切关注，其中一个重要方向是专一性调制剂的鉴定，但因通道研究时间短，目前未见专一性调制剂的报道。本项目前期研究从白额巨蟹蛛毒液中鉴定到了一个能增强酸激活的OTOP1通道电流的多肽毒素HpTx-V。该多肽含29个氨基酸残基，具有序列、结构新颖性及高活性、高专一性的特点，可作为OTOP1通道的分子探针和药理学工具。同时，前期研究和分析表明HpTx-V的活性与OTOP1通道质子门控或质子孔道的调控有关。鉴于此，本项目将在电生理活性、结构与功能关系、多肽与通道互作机制三个层面开展深入研究，阐明HpTx-V增强酸激活的OTOP1通道电流的分子机制，揭示专一性相互作用的结合位点，为解析该通道质子门控机制、质子孔道定位等关键科学问题提出新见解。

The OTOP1 channel is a new proton channel identified in 2018 and mediates the inward proton currents in tongue taste-sensing cells, which has been considered as a breakthrough in the related research field and is important to acid sensing behavior researches in mammalian animals. This has been attracted great attentions from scientists. It has been widely accepted that specific modulators are essential for the ion channel researches, therefore identification of specific modulators of the OTOP1 channel is also of great importance. However, no such modulators have been reported so far. Our group discovered a peptide (named HpTx-V) from the venom of the spider Heteropoda venatoria. HpTx-V contains 29 amino acid residues and shares low sequence similarity with and distinct disulfide linkage from the known peptide toxins, suggesting this peptide should have new sequence and structure scaffold. Moreover, its action on the OTOP1 channel displays high affinity and selectivity. Therefore, HpTx-V can be a useful molecular probe or pharmacological tool in the OTOP1 channel researches. Basing on data from peptide toxin-ion channel interaction and current studies of the OTOP1 channel, it was assumed that the activity of HpTx-V should be resulted from the regulatioin of proton-gating or proton pore of this channel. In the present study, we will continue to investigate the peptide electrophysiological activity, structure and activity relationship, and the peptide-channel interaction mechanism, which will elucidate the action mechanism underlying HpTx-V enhances the acid-activated OTOP1 channel currents. This study might provide some solid evidences and concepts for proton-gating modulation or proton pore identification of the OTOP1 channel.