FEMTOSECOND CORRELATION SPECTROSCOPIC PROBES

飞秒相关光谱探头

• 批准号: 6525518
• 负责人: SHAUL MUKAMEL
• 金额: $ 25.68万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6525518
• 关键词: carotenoids; computer program /software; electron transport; hydrogen bond; informatics; intermolecular interaction; mathematical model; mathematics; molecular dynamics; photochemistry; photosynthetic reaction centers; physical model; protein folding; quantum chemistry; solutions; spectrometry; stereochemistry; structural biology; technology /technique development; time resolved data; ubiquitin

The proposed research program will focus on the development of new computational algorithms for the microscopic simulation of complex biological molecules and their probing using coherent optical spectroscopies. Multiple-pulse techniques have the capacity to prepare electronic and vibrational degrees of freedom in nonequilibrium states and monitor their subsequent evolution, yielding femtosecond snapshots of dynamical events; energy transfer pathways, charge transfer, photoisomerization, and structural fluctuations. A molecular dynamics code which interfaces time-dependent quantum chemistry packages (density functional and the time dependent Hartree Fock) with semiclassical molecular dynamics algorithms for multipoint correlation functions will be developed. Multidimensional techniques should reveal the multitude of coherence sizes of photosynthetic complexes with specific spectroscopic signatures. Systems to be studied: LH2 of purple bacteria, the FMO complex, LHCII, CP29, and the Chlorosome. Nonlocal information on electron and energy transfer pathways, solvation dynamics, and vibrational relaxation will be extracted from fluorescence, pump probe, and three-pulse techniques. The application of these measurements towards refining the structure of photosynthetic antennae will be explored. Vibrational spectra of the amide I band and of OH hydrogen-bonded networks will be simulated. The structure and fluctuations of a small cyclic 10 residue polypeptide (Antamanide) and a globular 76-residue protein (Ubiquitin will be studied, focusing on Hydrogen bonding and Phenylalanine side chain dynamics in Antamanide and backbone and Glutamine sidechain dynamics in Ubiquitin. Protein folding in beta-peptides and its real-time probing by nonlinear spectroscopies will be investigated. An new spectroscopic algorithm for simulating excited-state photodynamics and relating it to protein-pigment interactions will be developed. Applications will be made to energy transfer processes in photodynamic therapy.

拟议的研究计划将侧重于开发新的计算算法，用于复杂生物分子的微观模拟及其使用相干光谱学的探测。多脉冲技术有能力在非平衡状态下制备电子和振动自由度，并监测它们的后续演变，产生动态事件的飞秒快照；能量转移途径、电荷转移、光异构化和结构波动。将开发一个分子动力学代码，将时变量子化学包（密度泛函和时变Hartree Fock）与多点相关函数的半经典分子动力学算法相结合。多维技术应该揭示具有特定光谱特征的光合复合体的大量相干尺寸。待研究的体系：紫色细菌的LH2、FMO复合物、LHCII、CP29和叶绿体。电子和能量转移途径、溶剂化动力学和振动弛豫的非局部信息将从荧光、泵探针和三脉冲技术中提取。这些测量对改进光合天线结构的应用将被探索。模拟了酰胺I带和OH氢键网络的振动谱。研究小环10残基多肽（Antamanide）和球形76残基蛋白（Ubiquitin）的结构和波动，重点研究Antamanide中的氢键和苯丙氨酸侧链动力学，以及Ubiquitin中的主干和谷氨酰胺侧链动力学。蛋白质折叠在β肽和它的实时探测非线性光谱将进行研究。一种新的光谱算法模拟激发态光动力学，并将其与蛋白质-色素相互作用联系起来。将应用于光动力疗法的能量转移过程。