A designed four-alpha-helix bundle that binds the volatile general anesthetic halothane with high affinity.
A designed four-alpha-helix bundle that binds the volatile general anesthetic halothane with high affinity.
复制标题
设计的四α螺旋束以高亲和力结合挥发性全身麻醉剂氟烷。
DOI：
10.1016/s0006-3495(00)76656-2
复制
发表时间：
2000
影响因子：
3.4
通讯作者：
Eckenhoff,RG
中科院分区：
文献类型：
--
作者：
Johansson,JS;Scharf,D;Davies,LA;Reddy,KS;Eckenhoff,RG
正在使用由具有疏水核心的四-α-螺旋束支架组成的定义模型系统来检查蛋白质上挥发性麻醉剂结合位点的结构特征。先前的工作表明，在疏水核中引入空腔可以提高麻醉剂的结合亲和力。用更易极化的蛋氨酸侧链取代亮氨酸，试图增强配体和蛋白质之间的分散力。与含亮氨酸的束（Kd =0.69±0.06mM）相比，所得到的束变体对氟烷结合具有改善的亲和力（Kd =0.20±0.01mM）。光亲和标记与14 C-氟烷揭示优先标记的W15残基在这两个肽，支持的观点，即荧光淬灭结合麻醉报告的结合能和位置的配体在疏水核心。酰胺氢交换率是相似的两束，表明结合亲和力的差异是由于蛋白质稳定性的变化。氟烷与两种四-α-螺旋束蛋白的结合稳定了天然折叠构象。束的分子动力学模拟说明存在的疏水核心，包含两个W15残基。这些结果表明，除了包装缺陷，增强分散力可能是重要的，在提供更高的亲和力麻醉剂结合位点。或者，甲硫氨酸取代对氟烷结合能学的影响可以反映对结合位点的改善的接近或结合口袋的尺寸的变构优化。最后，优先稳定的折叠蛋白质构象可能是吸入麻醉剂作用的基本机制。
The structural features of volatile anesthetic binding sites on proteins are being examined with the use of a defined model system consisting of a four-α-helix bundle scaffold with a hydrophobic core. Previous work has suggested that introducing a cavity into the hydrophobic core improves anesthetic binding affinity. The more polarizable methionine side chain was substituted for a leucine, in an attempt to enhance the dispersion forces between the ligand and the protein. The resulting bundle variant has an improved affinity (Kd=0.20±0.01mM) for halothane binding, compared with the leucine-containing bundle (Kd=0.69±0.06mM). Photoaffinity labeling with14C-halothane reveals preferential labeling of the W15 residue in both peptides, supporting the view that fluorescence quenching by bound anesthetic reports both the binding energetics and the location of the ligand in the hydrophobic core. The rates of amide hydrogen exchange were similar for the two bundles, suggesting that differences in binding affinity were not due to changes in protein stability. Binding of halothane to both four-α-helix bundle proteins stabilized the native folded conformations. Molecular dynamics simulations of the bundles illustrate the existence of the hydrophobic core, containing both W15 residues. These results suggest that in addition to packing defects, enhanced dispersion forces may be important in providing higher affinity anesthetic binding sites. Alternatively, the effect of the methionine substitution on halothane binding energetics may reflect either improved access to the binding site or allosteric optimization of the dimensions of the binding pocket. Finally, preferential stabilization of folded protein conformations may represent a fundamental mechanism of inhaled anesthetic action.
登录
查看更多内容
影响因子：
16.6
作者：
D. Rees;H. Komiya;T. Yeates;James P. Allen;G. Feher
通讯作者：
G. Feher
影响因子：
5.6
作者：
MCGREGOR, MJ;ISLAM, SA;STERNBERG, MJE
通讯作者：
STERNBERG, MJE
光合反应中心模型的合成：在合成四螺旋束多血红素蛋白的两个亚基之间组装的面卟啉对
DOI：
--
发表时间：
1996
期刊：
影响因子：
--
作者：
F. Rabanal;W. DeGrado;P. Dutton
通讯作者：
P. Dutton
强螺旋肽系列中的荧光猝灭：非共价途径在调节电子相互作用中的作用。
影响因子：
2.9
作者：
Basu,G;Anglos,D;Kuki,A
通讯作者：
Kuki,A
影响因子：
15
作者：
Johansson, JS;Gibney, BR;Dutton, PL
通讯作者：
Dutton, PL