Rhodopsin-transducin interface: studies with conformationally constrained peptides.
Rhodopsin-transducin interface: studies with conformationally constrained peptides.
复制标题
视紫红质-转导蛋白界面：构象受限肽的研究。
DOI：
10.1016/s0006-3495(01)75962-0
复制
发表时间：
2001
影响因子：
3.4
通讯作者：
Marshall,GR
中科院分区：
文献类型：
--
作者：
Arimoto,R;Kisselev,OG;Makara,GM;Marshall,GR
为了探究转导蛋白 (Gt) 和光激活视紫红质 (R*) 之间的相互作用，设计并合成了 14 个类似肽，限制了通过转移核欧沃豪瑟效应 (TrNOE) NMR 衍生的 Gtα C 端 11 个残基的 R* 结合结构的主链。大多数类似物能够结合 R*，支持 TrNOE 结构。受限肽的亲和力提高表明结合构象的预组织是有益的。发现Cys347是识别位点；特别是，侧链的游离巯基似乎对于 R* 结合至关重要。 Leu349 是另一个不变的残基。 Leu349 的 Ile 和叔亮氨酸 (Tle) 突变均显着降低了活性，表明 Leu 侧链与 R* 密切接触。 R* 的结构是根据各种实验数据，通过将螺旋 6 从其在基态视紫红质 (R) 晶体结构中的位置移动而由计算机生成的。当 TrNOE 结构与 R* 对接时，发现了 7 个可行的复合物，但没有与 R 对接。将类似肽建模到复合物中，并计算了它们的结合亲和力。 The predicted affinities were compared with the measured affinities to evaluate the modeled structures. R*/Gtα复合物的三种模型与实验数据显示出很强的相关性。
To probe the interaction between transducin (Gt) and photoactivated rhodopsin (R*), 14 analog peptides were designed and synthesized restricting the backbone of the R*-bound structure of the C-terminal 11 residues of Gtαderived by transferred nuclear Overhauser effect (TrNOE) NMR. Most of the analogs were able to bind R*, supporting the TrNOE structure. Improved affinities of constrained peptides indicated that preorganization of the bound conformation is beneficial. Cys347 was found to be a recognition site; particularly, the free sulfhydryl of the side chain seems to be critical for R* binding. Leu349 was another invariable residue. Both Ile andtert-leucine (Tle) mutations for Leu349 significantly reduced the activity, indicating that the Leu side chain is in intimate contact with R*. The structure of R* was computer generated by moving helix 6 from its position in the crystal structure of ground-state rhodopsin (R) based on various experimental data. Seven feasible complexes were found when docking the TrNOE structure with R* and none with R. The analog peptides were modeled into the complexes, and their binding affinities were calculated. The predicted affinities were compared with the measured affinities to evaluate the modeled structures. Three models of the R*/Gtαcomplex showed strong correlation to the experimental data.