Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
J Biol Chem. 2011 Nov 4;286(44):38168-38176. doi: 10.1074/jbc.M111.288993. Epub 2011 Sep 9.
Transient receptor potential ankyrin 1 (TRPA1) is a non-selective ion channel, which is expressed in nociceptor sensory neurons and transduces chemical, inflammatory, and neuropathic pain signals. Numerous non-reactive compounds and electrophilic compounds, such as endogenous inflammatory mediators and exogenous pungent chemicals, can activate TRPA1. Here we report a 16-Å resolution structure of purified, functional, amphipol-stabilized TRPA1 analyzed by single-particle EM. Molecular models of the N and C termini of the channel were generated using the I-TASSER protein structure prediction server and docked into the EM density to provide insight into the TRPA1 subunit organization. This structural analysis suggests a location for critical N-terminal cysteine residues involved in electrophilic activation at the interface between neighboring subunits. Our results indicate that covalent modifications within this pocket may alter interactions between subunits and promote conformational changes that lead to channel activation.
瞬时受体电位锚蛋白 1（TRPA1）是一种非选择性离子通道，表达于伤害感受器感觉神经元，转导化学、炎性和神经性疼痛信号。许多非反应性化合物和亲电性化合物，如内源性炎性介质和外源性刺激性化学物质，能够激活 TRPA1。在此，我们报道了经纯化和功能分析的、用两性离子稳定的 TRPA1 的单颗粒电镜解析结构，分辨率为 16 Å。通道的 N 和 C 末端的分子模型是使用 I-TASSER 蛋白结构预测服务器生成的，并对接入到电镜密度中，以深入了解 TRPA1 亚基的组织。该结构分析提示，在相邻亚基界面处，涉及亲电激活的关键 N 末端半胱氨酸残基的位置。我们的结果表明，该口袋内的共价修饰可能改变亚基之间的相互作用，并促进导致通道激活的构象变化。
