iHuman Institute, ShanghaiTech University, China.
Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
FEBS Lett. 2019 May;593(10):1113-1121. doi: 10.1002/1873-3468.13382. Epub 2019 Apr 21.
Large membrane proteins such as G protein-coupled receptors (GPCRs) are difficult for NMR study due to severe signal overlaps and unfavorable relaxation properties. We used a trimethylsilyl (TMS) group as a reporter group for H NMR study of conformational changes in proteins, utilizing high-intensity H NMR signals near 0 p.p.m. The β -adrenergic receptor was labeled with TMS groups at two cysteines located at the cytoplasmic ends of helices VI and VII. Binding of various ligands led to changes in H NMR signals, which manifested that helix VI is sensitive to G protein-specific activation, whereas helix VII is sensitive to β-arrestin-specific activation. Thus, the TMS group is a useful reporter group in NMR for studying conformational changes in membrane proteins such as GPCRs.
大膜蛋白，如 G 蛋白偶联受体（GPCRs），由于信号严重重叠和不利的弛豫性质，因此难以进行 NMR 研究。我们使用三甲基硅基（TMS）基团作为报告基团，利用接近 0 p.p.m. 的高强度 H NMR 信号，对蛋白质构象变化进行 H NMR 研究。β-肾上腺素能受体在位于螺旋 VI 和 VII 胞质末端的两个半胱氨酸上标记有 TMS 基团。与各种配体的结合导致 H NMR 信号发生变化，这表明螺旋 VI 对 G 蛋白特异性激活敏感，而螺旋 VII 对β-arrestin 特异性激活敏感。因此，TMS 基团是 NMR 中研究 GPCR 等膜蛋白构象变化的有用报告基团。
