Multidimensional Femtosecond Correlation Spectroscopic Probe Biomolecules

描述(由申请人提供)：将开发模拟技术来预测生物分子对红外和可见光脉冲序列的非线性响应，并将它们与各种二级结构基序、结构波动和动力学过程联系起来。这些多维信号提供了动力学事件的飞秒快照，将使用从从头算密度泛函和MD代码获得的多点关联函数进行计算和分析。将使用从非均匀电场下单个生色团的电子结构计算获得的静电图，对环境(主链构象、侧链和溶剂)的波动的振动特征进行大规模模拟。 将模拟由温度跃变、嵌入开关的光异构化以及由光学诱导的偶极触发的蛋白质折叠路径的特定红外特征。使用新的光偏振构型的相干时间分辨手性光谱探测器将被研究。利用与核磁共振的类比，将开发出相干、振动和电子光谱中的脉冲序列的设计策略。相干控制算法和灵敏度分析将被用来根据球状蛋白质中特定的二级结构基序定制脉冲形状，解开复杂的光谱，并将它们与特定的结构和动力学过程联系起来。酰胺I带的二维振动光谱将用于区分淀粉样蛋白纤维的平行和反平行的β片层结构。其他应用将被用于DNA碱基对和光合作用聚集体。在多维红外信号中，氨基酸残基之间以及与水的氢键的特定特征将被预测。

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.