Photoinduced isomerization of the Photoactive Yellow Protein chromophore: a detailed theoretical investigation

光活性黄色蛋白发色团的光诱导异构化：详细的理论研究

• 批准号: 64900238
• 负责人: Professor Dr. Lorenz S. Cederbaum
• 金额: --
• 依托单位: Forschungsgruppe Theoretische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/64900238?language=en
• 关键词: Photoinduced; isomerization; Photoactive; Yellow; Protein

In this project, theory - including large-scale electronic structure and dynamical calculations - will be applied to provide detailed insight into the initial photoevents in a biological photoreceptor - the Photoactive Yellow Protein (PYP). We focus on the very earliest events in the PYP photocycle, related to the trans-to-cis isomerization of the -C=C- double bond of the PYP co-factor, the deprotonated p-hydroxycinnamoyl chromophore. The mechanism and dynamics of the isomerization process can be characterized as highly complex due to the involvement of several coordinates (two torsions and one bending mode) and the strong impact of the chromophore’s local environment. Our theoretical analysis will rest on quantum chemistry electronic structure and (semi-classical and quantum) dynamical calculations for the chromophore in the native (protein) environment and in a specific (model) environment. For the chromophore in the protein environment, the main emphasis will be placed on (i) establishing inhomogeneities in the dark-state of PYP and (ii) scrutinizing the initial phase of the chromophore’s isomerization. For the model environment, the main focus will be put on elucidating the role of the hydrogen out-of-plane (HOOP) coordinate in the isomerization process. Rationalization of these issues should illuminate such yet obscure aspects as the photoactive (isomerizable) form of PYP, implication/interplay of the isomerization coordinates, the reaction pathway and mechanism of the process. Acquiring control over the chromophore’s isomerization is considered an exciting perspective.

在该项目中，理论（包括大规模电子结构和动力学计算）将用于详细了解生物光感受器（光活性黄色蛋白（PYP））中的初始光事件。我们关注 PYP 光循环中最早的事件，与 PYP 辅因子（去质子化的对羟基肉桂酰发色团）的 -C=C- 双键的反式异构化相关。由于涉及多个坐标（两种扭转和一种弯曲模式）以及发色团局部环境的强烈影响，异构化过程的机制和动力学可以被描述为高度复杂。我们的理论分析将依赖于原生（蛋白质）环境和特定（模型）环境中发色团的量子化学电子结构和（半经典和量子）动力学计算。对于蛋白质环境中的发色团，主要重点将放在（i）建立 PYP 暗状态下的不均匀性和（ii）仔细检查发色团异构化的初始阶段。对于模型环境，主要重点将放在阐明氢面外（HOOP）坐标在异构化过程中的作用。这些问题的合理化应该阐明诸如 PYP 的光活性（可异构化）形式、异构化坐标的含义/相互作用、反应途径和过程机制等模糊方面。获得对发色团异构化的控制被认为是一个令人兴奋的观点。