Multidimensional Femtosecond Correlation Spectroscopic Probe Biomolecules

描述（申请人提供）：将开发用于预测生物分子对红外和可见光脉冲序列的非线性响应，并将其与各种二级结构基序，结构波动和动态过程联系起来的模拟技术。这些多维信号提供了动态事件的飞秒快照，将使用从头算密度泛函和MD代码获得的多点相关函数进行计算和分析。将使用从受到非均匀电场的单个发色团的电子结构计算中获得的静电图，对环境波动（主链构象、侧链和溶剂）的振动特征进行大规模模拟。

DESCRIPTION (provided by applicant): Simulation techniques for predicting the nonlinear response of biomolecules to sequences of infrared and visible pulses, and connecting them to various secondary structure motifs, structure fluctuations and dynamical processes, will be developed. These multidimensional signals, which provide femtosecond snapshots of dynamical events, will be calculated and analyzed, using multipoint correlation functions obtained from ab initio density functional and MD codes. Large scale simulations of vibrational signatures of fluctuations of the environment (backbone conformations, side chains and solvent) will be performed, using an electrostatic map obtained from electronic structure calculations of individual chromophores subjected to a nonuniform electric field. Specific infrared signatures of protein folding pathways, triggered by temperature jump, photoisomerization of an embedded switch, and by optically induced dipoles will be simulated. Coherent time resolved spectroscopic probes of chirality which use novel light polarization configurations will be studied. Design strategies for pulse sequences in coherent.vibrational and electronic spectroscopies, drawing upon the analogy with NMR, will be developed. Coherent control algorithms and sensitivity analysis will be used to tailor pulse shapes to specific secondary structural motifs in globular proteins, disentangle complex spectra and relate them to specific structural and dynamical processes. Two dimensional vibrational spectra of the amide I band will be used to distinguish between parallel and anti-parallel beta sheet structures of Amyloid Fibrils. Other applications will be made to DNA base pairs and photosynthetic aggregates. Specific signatures of hydrogen bonding between amino acid residues, and with water in multidimentional infrared signals, will be predicted.