Excited state dynamics in the early stages of the bR and Rh photocycle

bR 和 Rh 光循环早期的激发态动力学

• 批准号: 15499286
• 负责人: Professor Dr. Thomas Frauenheim
• 金额: --
• 依托单位: Abteilung für Theoretische Chemische Biologie
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/15499286?language=en
• 关键词: Excited; state; dynamics; early; stages

The very first step in the complex function of the retinal proteins is the absorption of light which is followed by an isomerization of the chromophore within the protein. The high speed, efficiency and selectivity of the process are directly related to the optimized molecular arrangement of the binding pocket.Different factors have so far limited the theoretical description of theses systems. First, the reaction occurs in an excited electronic state for which quantum chemical calculations provide accurate solutions only at high computational cost. Second, the dynamics in the retinal proteins are believed to happen an strongly coupled potential energy surfaces. This makes the use of advanced nonadiabatic molecular dynamics schemes mandatory in order to obtain realistic values for reaction time scales and quantum yields. Finally, the complexity of the protein interaction with the chromophore requires the inclusion of a large part of the binding pocket in structural models for the active site, which involves a high computational effort. In the first half of this project we developed methods which cope with these specific problems and can be used in the second half to analyze the early stages of the bR and Rh photocycies. These calculations will provide structural Information an intermediates in the photocycle and lead to a detailed picture of the complex retinal photoreaction.

视网膜蛋白质复杂功能的第一步是吸收光，随后是蛋白质内发色团的异构化。该工艺的高速度、高效率和选择性与结合袋分子排列的优化直接相关。迄今为止，各种因素限制了这些系统的理论描述。首先，反应发生在激发态，量子化学计算只能在高计算成本下提供精确的解决方案。其次，视网膜蛋白的动态被认为发生在强耦合的势能表面。这使得必须使用先进的非绝热分子动力学方案，以便获得反应时间尺度和量子产率的实际值。最后，由于蛋白质与发色团相互作用的复杂性，需要在活性位点的结构模型中包含很大一部分结合袋，这需要很高的计算量。在这个项目的前半部分，我们开发了处理这些具体问题的方法，可以在后半段用于分析bR和Rh光合作用的早期阶段。这些计算将提供光循环中间体的结构信息，并导致复杂视网膜光反应的详细图像。