World Premier International Research Center Initiative, Nano Life Science Institute, Kanazawa University, Kanazawa 920-1192, Japan.
Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan.
Proc Natl Acad Sci U S A. 2023 May 16;120(20):e2301013120. doi: 10.1073/pnas.2301013120. Epub 2023 May 8.
Transient receptor potential vanilloid member 1 (TRPV1) is a heat and capsaicin receptor that allows cations to permeate and cause pain. As the molecular basis for temperature sensing, the heat capacity (Δ) model [D. E. Clapham, C. Miller, , 19492-19497 (2011).] has been proposed and experimentally supported. Theoretically, heat capacity is proportional to a variance in enthalpy, presumably related to structural fluctuation; however, the fluctuation of TRPV1 has not been directly visualized. In this study, we directly visualized single-molecule structural fluctuations of the TRPV1 channels in a lipid bilayer with the ligands resiniferatoxin (agonist, 1,000 times hotter than capsaicin) and capsazepine (antagonist) by high-speed atomic force microscopy. We observed the structural fluctuations of TRPV1 in an apo state and found that RTX binding enhances structural fluctuations, while CPZ binding suppresses fluctuations. These ligand-dependent differences in structural fluctuation would play a key role in the gating of TRPV1.
瞬时受体电位香草酸亚型 1（TRPV1）是一种热和辣椒素受体，允许阳离子渗透并引起疼痛。作为温度感应的分子基础，热容（Δ）模型[D.E. Clapham、C. Miller，19492-19497（2011）。]已被提出并得到实验支持。从理论上讲，热容与焓变的方差成正比，这可能与结构波动有关；然而，TRPV1 的波动尚未被直接可视化。在这项研究中，我们通过高速原子力显微镜直接可视化了配体树脂毒素（激动剂，比辣椒素热 1000 倍）和辣椒素（拮抗剂）存在下脂质双层中 TRPV1 通道的单分子结构波动。我们观察到 TRPV1 在apo 状态下的结构波动，发现 RTX 结合增强了结构波动，而 CPZ 结合抑制了波动。这些配体依赖性的结构波动差异将在 TRPV1 的门控中发挥关键作用。
