Probing the rhodopsin cavity with reduced retinal models at the CASPT2//CASSCF/AMBER level of theory
Probing the rhodopsin cavity with reduced retinal models at the CASPT2//CASSCF/AMBER level of theory
复制标题
DOI：
10.1021/ja035087d
复制
发表时间：
2003-06-11
影响因子：
15
通讯作者：
Olivucci, M
中科院分区：
文献类型：
--
作者：
Ferré, N;Olivucci, M
我们发现，以前用于研究真空中视觉受体视紫红质(Rh)发色团基态和激发态的从头算CASPT2//CASSCF策略可以成功地在QM/MM方案中实现，从而允许CASPT2//CASSCF/Amber几何结构优化和蛋白质激发态性质的评估。研究了含有不同还原发色团的两种受体模型(Rh-1和Rh-2)。结果表明，Rh-2分子具有一个具有正确螺旋度的生色团平衡结构和一个仅比观测值蓝移52 nm的λ极大值。这一结果应该为对视觉过程中涉及的早期激发态瞬变物种进行定性正确的从头算QM/MM建模开辟了道路。
We show that the ab initio CASPT2//CASSCF strategy previously used to investigate the ground and excited states of the chromophore of the vision receptor rhodopsin (Rh) in vacuo can be successfully implemented in a QM/MM scheme allowing for CASPT2//CASSCF/AMBER geometry optimization and excited state property evaluationin proteins. Two receptor models (Rh-1andRh-2) incorporating different reduced chromophores are investigated. It is shown thatRh-2features a chromophore equilibrium structure with the correct helicity and a λmaxthat is only 52 nm blue-shifted from the observed value. This result should open the way to a qualitatively correct ab initio QM/MM modeling of the early excited state transient species involved in the vision process.