...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >11-cis-Retinal protonated schiff base: influence of the protein environment on the geometry of the rhodopsin chromophore
【24h】

11-cis-Retinal protonated schiff base: influence of the protein environment on the geometry of the rhodopsin chromophore

机译：11-顺式视网膜质子化席夫碱：蛋白质环境对视紫红质发色团的几何形状的影响。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Density functional theory (DFT) calculations based on the self-consistent-charge tight-binding approximation have been performed to study the influence of the protein pocket on the 3-dimensional structure of the 11-cis-retinal Schiff base (SB) chromophore. Starting with an effectively planar chromophore embedded in a protein pocket consisting of the 27 next-nearest amino acid, the relaxed chromophore geometry resulting from energy optimization and molecular dynamics (MD) simulations has yielded novel insights with respect to the following questions: (i) The conformation of the beta-ionone ring. The protein pocket tolerates both conformations, 6-s-cis and 6-s-trans, with a total energy difference of 0.7 kcal/mol in favor of the former. Of the two possible 6-s-cis conformations, the one with a negative twist angle (optimized value: -35 deg C) is strongly favored, by 3.6 kcal/mol, relative to the one in which the dihedral is positive.(ii) Out-of-plane twist of the chromophore. The environment induces a nonplanar helical deformation of the chromophore, with the distortions concentrated in the central region of the chromophore, from C10 to C13. The dihedral angle between the planes formed by the bonds from C7 to C10 and from C13 to C15 is 42 deg. (iii) The absolute configuration of the chromophore. The dihedral angle about the C12-C13 bond is +170 deg from planar c-cis, which imparts a positive helicity on the chromophore, in agreement with earlier considerations based on theoretical and spectroscopic evidence.
机译：已经进行了基于自洽电荷紧密结合近似的密度泛函理论（DFT）计算，以研究蛋白质袋对11-顺-视网膜席夫碱（SB）发色团3维结构的影响。从嵌入在由27个下一个最近氨基酸组成的蛋白质袋中的有效平面发色团开始，通过能量优化和分子动力学（MD）模拟获得的宽松的发色团几何形状对以下问题产生了新颖的见解：（i） β-紫罗兰酮环的构象。蛋白质袋可耐受6-s-顺式和6-s-反式两种构型，总能量差为0.7 kcal / mol，有利于前者。在两种可能的6-s-顺式构象中，相对于二面角为正的构型，强烈推荐使用具有负扭转角（最佳值：-35摄氏度）的3.6 kcal / mol的构象。 ）生色团的面外扭曲。环境导致生色团发生非平面螺旋形变形，变形集中在从C10到C13的生色团的中心区域。由C7至C10和C13至C15的键形成的平面之间的二面角为42度。 （iii）生色团的绝对构型。围绕C12-C13键的二面角与平面c-cis呈+170度，这赋予发色团正螺旋性，这与基于理论和光谱证据的早期考虑相符。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号