蛋白质二维红外相干光谱的理论研究(英文)

多肽对红外激光脉冲的非线性响应中包含了丰富的结构动力学信息。本文以肽链的酰胺振动跃迁为例,提出了模拟二维红外相干光谱的理论方案。文中首先介绍了激子模型下非线性响应的微扰图像,并基于激子模型、经典分子动力学模拟和密度泛函静电势,构建酰胺振动模式有效波动哈密顿量。采用随机刘维尔方程(SLE)、数值演化(NP)、高斯波动的累积展开(CGF)等方法计算非线性响应光谱。文章最后对多肽及多肽复合物等体系的二维红外信号进行模拟和讨论。

Coherent Two Dimensional Infrared Spectroscopy of Proteins:Concepts and Simulations

The nonlinear optical response of peptide molecules to femtosecond infrared pulse sequences contains rich information on their structure,fluctuations and motions.We reviewed in this article the basic concepts as well as the simulation protocol for 2DIR signals associated with the amide backbone vibrational transitions of proteins.Starting with a general introduction of the perturbative picture of nonlinear optical response of excitonic systems,an introduction is given for constructing an effective fluctuating vibrational Hamiltonian based on classical MD simulation and a DFT electrostatic map.Several techniques for simulating the nonlinear response using the fluctuating Hamiltonian are then surveyed,these include the stochastic Liouville equations(SLE),numerical propagation(NP) and cumulant expansion of Gaussian fluctuation(CGF).Applications are presented to two dimensional infrared signal of peptides and peptide complexes.