Resonance Raman Studies of Electron-Nuclear Coupling, Time Resolved Dynamics, and Magnetic Perturbations of Biomolecules

该研究将利用共振拉曼散射及其时域类似物相干脉冲散射来探测血红素蛋白（肌红蛋白、血红蛋白和细胞色素c）和光合系统（光收集天线和反应中心）等生物分子的电子和核结构/功能关系。相关的技术，如电子吸收和红外光谱，也将被利用，并将开发连接各种实验测量的理论模型。绝对截面测量将用于直接提取电子-核耦合强度，而光学吸收线形的温度依赖性产生低频运动的耦合及其在阻尼中的作用。对低频蛋白质运动的研究将与超快脉冲散射技术相辅相成，这种技术可以实时测量这种运动。还提出了进一步的实验和理论研究，包括蛋白质分布的光谱和动力学效应。动态研究将包括在各种样品条件下测量和分析配体结合和电子转移，以及设计用于监测蛋白质折叠和构象松弛的泵/探针实验。用Stokes/反Stokes拉曼散射跟踪激光介导的热扰动。光还原引起的动态过程的研究和生物单晶的动力学研究也将得到扩展。一般的科学目标是更好地理解大型生物重要分子的运动动力学及其吸收和共振光散射特性。目的是应用这些知识来阐明它们的作用机制。这些研究不仅在它们与生物科学的关系方面具有重要意义，而且在它们与我们对光与凝聚态复杂材料系统相互作用的理解方面也具有重要意义。＊＊＊

9405979 Champion The proposed research will utilize resonance Raman scattering and its time domain analog, coherent impulsive scattering, to probe the electronic and nuclear structure/function relationships of biological molecules such as heme proteins (myoglobin, hemoglobin and cytochrome c) and photosynthetic systems (light harvesting antennae and reaction centers). Related techniques, such as electronic absorption and infrared spectroscopy, will also be utilized, and theoretical models that link a variety of experimental measurements will be developed. Absolute cross- section measurements will be used to directly extract the electron-nuclear coupling strengths while the temperature dependence of the optical absorption lineshape yields the coupling of low frequency motion and its role in damping. The studies of low frequency protein motion will be complemented with ultrafast impulsive scattering techniques, which allow real time measurement of such motion. Further experimental and theoretical studies involving the spectroscopic and kinetic effects of protein distributions are also proposed. Dynamic studies will include the measurement and analysis of ligand binding and electron transfer under a wide variety of sample conditions, as well as pump/probe experiments designed to monitor protein folding and conformational relaxations. Laser mediated thermal perturbations will be followed using Stokes/anti-Stokes Raman scattering. Studies of dynamic processes induced by photoreduction and kinetic studies of biological single crystals will also be extended. %%% The general scientific objectives are to achieve a better understanding of the dynamics of motion of large biologically important molecules and their absorption and resonant light scattering properties. The aim is to apply this knowledge to elucidate their mechanism of action. These studies are significant not only in their relationship to the biological sciences, but also in their connection to our u nderstanding of the interaction of light with complex material systems in the condensed phase. ***