Jung H, Windhaber R, Palm D, Schnackerz K D
Theodor-Boveri-Institut für Biowissenschaften, Universität Würzburg, F.R.G.
Biochemistry. 1996 May 21;35(20):6399-405. doi: 10.1021/bi952575s.
The peptide T345-359 representing the fourth intracellular loop of the avian beta-adrenoceptor has been shown to strongly inhibit receptor-mediated adenylate cyclase activity [Münch, G., Dees, C., Hekman, M., & Palm, D. (1991) Eur. J. Biochem. 198, 357-364]. Circular dichroism and two-dimensional 1H NMR techniques were used to investigate the three-dimensional structure of the peptide in trifluoroethanol, phospholipid micelles, and small unilamellar phospholipid vesicles. The prepared vesicles were tested for size distribution and stability by using electron microscopy, photon correlation spectroscopy, and 31P NMR spectroscopy. The peptide T345-359 adopted a predominantly alpha-helical conformation in either trifluoroethanol or phospholipid micelles and vesicles. No structural differences were found for the conformation of the peptide in the presence of phospholipid micelles or vesicles, respectively, using 2D 1H NMR techniques, suggesting a unique conformation of T345-359 when associated with model membranes. A computer-aided model of the micelle-associated peptide was derived. The relevance of the 3D structure of the intracellular loops of receptors to communicate with the G protein in the signal transduction cascade is discussed.
代表禽β-肾上腺素能受体第四细胞内环的肽T345-359已被证明能强烈抑制受体介导的腺苷酸环化酶活性[明希，G.，迪斯，C.，赫克曼，M.，&帕尔姆，D.（1991年）《欧洲生物化学杂志》198，357 - 364]。利用圆二色性和二维1H NMR技术研究了该肽在三氟乙醇、磷脂微团和小单层磷脂囊泡中的三维结构。通过电子显微镜、光子相关光谱和31P NMR光谱对制备的囊泡的大小分布和稳定性进行了测试。肽T345-359在三氟乙醇或磷脂微团及囊泡中主要呈α-螺旋构象。使用二维1H NMR技术，分别在磷脂微团或囊泡存在的情况下，未发现该肽构象的结构差异，这表明T345-359与模型膜结合时具有独特的构象。推导了与微团相关的肽的计算机辅助模型。讨论了受体细胞内环的三维结构在信号转导级联中与G蛋白通讯的相关性。
