The capsaicin binding affinity of wildtype and mutant TRPV1 ion channels.
The capsaicin binding affinity of wildtype and mutant TRPV1 ion channels.
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DOI：
10.1016/j.jbc.2023.105268
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发表时间：
2023-11
影响因子：
4.8
通讯作者：
Zheng, Jie
中科院分区：
文献类型：
--
作者：
Li, Shisheng;Zheng, Jie
辣椒素和树脂毒素等香草酸类化合物是瞬时受体电位香草酸亚家族成员 1 的高度选择性和有效的激活剂，成员 1 是一种热和疼痛感知的伤害感受器。然而，尽管通过电生理学、结构和计算方法进行了深入研究，但理解瞬时受体电位香草酸亚家族成员 1 功能的关键——内在香草酸结合亲和力仍然未知。在这项研究中，我们通过用多联体分离每个亚基的单独结合步骤来确定生理条件下辣椒素的结合亲和力。我们估计野生型亚基的辣椒素关联常数约为 106 M−1，而 Y511A 突变亚基的辣椒素关联常数要低一百倍，约为 104 M−1。 Y511A 突变位于香草酸结合袋的入口处，可降低结合亲和力，但对激活门控没有明显影响。我们进一步确认香草醛结合步骤之间几乎没有协同性。基于独立结合和同等协作的亚基门控的模型可以准确描述辣椒素的激活。
Vanilloids such as capsaicin and resiniferatoxin are highly selective and potent activators for transient receptor potential vanilloid subfamily, member 1, a nociceptor for heat and pain perception. However, the intrinsic vanilloid binding affinity, key for understanding transient receptor potential vanilloid subfamily, member 1 function, remains unknown despite intensive investigations by electrophysiological, structural, and computational methods. In this study, we determined capsaicin binding affinity under physiological conditions by isolating individual binding steps to each subunit with concatemers. We estimated the capsaicin association constant of a wildtype subunit to be in the order of 106 M−1 and that of the Y511A mutant subunit to be a hundred times lower, in the order of 104 M−1. The Y511A mutation, located at the entrance of the vanilloid binding pocket, reduces binding affinity without a noticeable effect on activation gating. We further affirmed that there is little cooperativity between vanilloid binding steps. Models based on independent binding and equally cooperative subunit gating can accurately describe capsaicin activation.