Complete-active-space self-consistent-field/Amber parameterization of the Lys296-retinal-Glu113 rhodopsin chromophore-counterion system

被引：59

作者：

Ferré, N

Cembran, A

Garavelli, M

Olivucci, M

机构：

[1] Univ Siena, Dipartimento Chim, I-53100 Siena, Italy

[2] Univ Bologna, Dipartimento Chim G Ciamician, I-40126 Bologna, Italy

[3] Ctr Studio Sistemi Complessi, I-53100 Siena, Italy

来源：

THEORETICAL CHEMISTRY ACCOUNTS | 2004年 / 112卷 / 04期

关键词：

rhodopsin; retinal; photoisomerization; quantum mechanics; molecular mechanics; parameterization;

D O I：

10.1007/s00214-004-0593-0

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

A special hybrid quantum mechanics/molecular mechanics forcefield is defined, parameterized and validated for studying the photoisomerization path of the retinal chromophore in the rhodopsin protein. It couples a multireference ab initio Hamiltonian (CASSCF and second-order multireference many-body perturbation theory using a CASSCF reference) to describe the chromophore while the rest of the protein is approximated with the Amber forcefield. The frontier has been carefully parameterized in order to reproduce full quantum mechanics torsional energy profiles, for both the ground state and the first excited state. It is also shown that replacing the chromophore counterion with point charges is a valid approximation. This result is interpreted in terms of a cancellation effect for which a possible explanation is given.

引用

页码：335 / 341

页数：7

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