Department of Biophysics, and Kidney Disease Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310058, Hangzhou, Zhejiang Province, China.
Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, 650223, Kunming, Yunnan, China.
Nat Commun. 2020 Jul 29;11(1):3790. doi: 10.1038/s41467-020-17582-x.
Menthol in mints elicits coolness sensation by selectively activating TRPM8 channel. Although structures of TRPM8 were determined in the apo and liganded states, the menthol-bounded state is unresolved. To understand how menthol activates the channel, we docked menthol to the channel and systematically validated our menthol binding models with thermodynamic mutant cycle analysis. We observed that menthol uses its hydroxyl group as a hand to specifically grab with R842, and its isopropyl group as legs to stand on I846 and L843. By imaging with fluorescent unnatural amino acid, we found that menthol binding induces wide-spread conformational rearrangements within the transmembrane domains. By Φ analysis based on single-channel recordings, we observed a temporal sequence of conformational changes in the S6 bundle crossing and the selectivity filter leading to channel activation. Therefore, our study suggested a 'grab and stand' mechanism of menthol binding and how menthol activates TRPM8 at the atomic level.
薄荷醇通过选择性激活 TRPM8 通道引发凉爽感。尽管已经确定了 TRPM8 的apo 和配体状态结构,但薄荷醇结合状态仍未解决。为了了解薄荷醇如何激活通道,我们将薄荷醇对接至通道,并通过热力学突变循环分析系统地验证我们的薄荷醇结合模型。我们观察到薄荷醇使用其羟基作为一只手,专门抓住 R842,并用异丙基作为腿,站在 I846 和 L843 上。通过用荧光非天然氨基酸成像,我们发现薄荷醇结合诱导跨膜域内广泛的构象重排。通过基于单通道记录的Φ分析,我们观察到 S6 束交叉和选择性过滤器中的构象变化的时间序列,导致通道激活。因此,我们的研究提出了薄荷醇结合的“抓取和站立”机制,以及薄荷醇如何在原子水平上激活 TRPM8。