紫外线色素的光谱调整:一个螺旋间锁定机制
Sivakumar Sekharan1, Victoria L Mooney, Ivan Rivalta
1Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107 United States.
Journal of the American Chemical Society
|December 4, 2013
概括
紫外线 (UV) 圆色素表现出一种独特的无质子 Schiff 基 (USB11) 染色体. 一个特定的突变 (F86Y) 导致USB11和质子 Schiff 基 (PSB11) 形式的共存,这些形式由螺旋间锁 (IHL) 稳定.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 视觉科学 视觉科学 视觉科学
背景情况:
- 紫外线 (UV) 色素对于理解脊椎动物视觉演变至关重要.
- 紫外线颜料与可见吸收颜料的区别在于它们的无质子希夫基 (USB11) 染色体,与可见颜料中的质子希夫基 (PSB11) 不同.
- 紫外线颜料中的突变 (F86Y) 导致USB11和PSB11在生理pH下共存,这一现象需要分子解释.
研究的目的:
- 阐明USB11和PSB11染色体在生理pH值下共存的分子基础.
- 研究USB11环境在紫外线色素中的光谱调中的作用.
主要方法:
- 利用了西伯利亚仓鼠紫外线 (SHUV) 色素的突变性研究.
- 使用光谱 (紫外线) 分析.
- 使用DFT-QM/MM (SORCI+Q//B3LYP/6-31G(d):Amber96) 方法进行了理论计算.
主要成果:
- F86Y突变诱导了PSB11染色体的形成.
- 这种PSB11形式是由"螺旋间锁" (IHL) 稳定,其中涉及TM6,TM2和TM3跨膜螺旋之间结网络.
- 特定的氨基酸残留物 (Y265,F86Y,G117,S118,A114,E113) 和水分子w2c是IHL的组成部分.
结论:
- 螺旋间锁 (IHL) 机制稳定了突变紫外线颜料中的质子 Schiff 基 (PSB11) 形式.
- IHL限制了跨膜螺旋TM6的移位,影响了紫外线颜料中的光谱调整.
- 这项研究为UV色素的光谱调和激活机制提供了分子洞察力.
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