Unidade de Resonancia Magnética, RIAIDT, Universidad de Santiago de Compostela, Santiago de Compostela, Spain.
Bioorg Med Chem. 2010 Feb 15;18(4):1583-90. doi: 10.1016/j.bmc.2010.01.004. Epub 2010 Jan 11.
The study of the interaction of ghrelin (1), the endogenous ligand for the GH secretagogues receptor (GHS-R1a), and des-acyl ghrelin (2) with the GHS-R1a by NMR using living cells is presented, using GHS-R1a stably transfected cell lines (CHO and HEK 293) and wild type cells. Therefore, the interaction of 1 and 2 with the GHS-R1a receptor has been performed using quasi-physiological conditions. Ghrelin (1), showed a higher number of residues affected by chemical shift perturbation (CSP) or chemical shift exchange (CSE) effects: Ser3, Phe4, Leu5, Val12, Gln13/Gln14, Lys16/Lys19, Glu17 and Lys24 were much more affected in 1 than in des-acyl ghrelin (2). The chemical shift index CSI values indicated the presence of a possible alpha-helical region between Glu8 and Lys20 for ghrelin (1). After analysing the NMR data, two possible structures have arisen, which present different proline rotamers: the EEZE and the EZEZ conformers, at positions Pro7, Pro21, Pro22 and Pro27, respectively, keeping a left-handed alpha-helix from Glu8 to Lys20. These experimental evidences might imply that the GHS-R1a receptor is acting as a prolyl-cis/trans isomerase.
本文使用稳定转染 GHS-R1a 的 CHO 和 HEK 293 细胞系和野生型细胞，通过核磁共振（NMR）研究了内源性 GH 分泌素受体（GHS-R1a）配体 ghrelin（1）和去酰基 ghrelin（2）与 GHS-R1a 的相互作用。因此，在准生理条件下进行了 1 和 2 与 GHS-R1a 受体的相互作用研究。ghrelin（1）中受化学位移扰动（CSP）或化学位移交换（CSE）影响的残基数量较多：Ser3、Phe4、Leu5、Val12、Gln13/Gln14、Lys16/Lys19、Glu17 和 Lys24 受到的影响比去酰基 ghrelin（2）更大。化学位移指数 CSI 值表明 ghrelin（1）中 Glu8 和 Lys20 之间可能存在一个潜在的α-螺旋区域。分析 NMR 数据后，出现了两种可能的结构，它们在 Pro7、Pro21、Pro22 和 Pro27 处具有不同的脯氨酸旋转异构体：EEZE 和 EZEZ 构象，分别保持了从 Glu8 到 Lys20 的左手α-螺旋。这些实验证据可能意味着 GHS-R1a 受体充当脯氨酰顺/反异构酶。
