Raman Spectroscopy and Pressure Studies of Protein Dynamics

压力和温度的变化与时间分辨拉曼光谱相结合，研究与蛋白质功能相关的反应参数和运动。主要的焦点是两个原型过程：配体与肌红蛋白的结合和质子泵细菌视紫红质的光能转导。通过改变压力和温度，使蛋白质达到吉布斯自由能表面的特定状态。突然的外部扰动，例如压力跳跃或激光闪光，会引发反应或松弛。改变位置和强度的振动模式的动力学研究探索了高度简并的能量表面和松弛现象。除了监测可见光中的拉曼波段外，我们还使用近红外激发来获得在没有期望的光化学和共振增强的情况下的拉曼光谱。这些研究为肌红蛋白和细菌视紫红质构象能面排列、压力对蛋白质动力学的影响以及细菌视紫红质活化的分子结构提供了新的信息。蛋白质维持生物功能的动力学结构是通过未折叠多肽链的能量和体积变化来区分的。在可变温度和压力下的位点选择光谱研究提供了对稳定生物活性分子的分子相互作用的相对能量尺度的见解。振动标记带用于监测肌红蛋白和细菌视紫红质的结构变化和运动，并将它们与蛋白质功能联系起来。由于蛋白质在热力学、结构和动力学性质上与许多无序系统（如玻璃）有相似之处，因此这项研究的新见解将对其他科学领域的无序和复杂性模型产生影响。＊＊＊

9305711 Schulte Variations in pressure and temperature are combined with time- resolved Raman spectroscopy to study reaction parameters and motions relevant for protein function. The principal focus is on two prototype processes: ligand binding to myoglobin and light energy transduction in the proton-pump bacteriorhodopsin. The protein is brought to a particular state of the Gibbs free energy surface by changing pressure and temperature. A sudden external perturbation, for instance a pressure jump or a laser flash, initiates a reaction or a relaxation. Kinetic studies of vibrational modes that change in position and intensity explore the highly degenerate energy surface and relaxation phenomena. In addition to monitoring Raman bands in the visible we use excitation in the near-infrared to obtain Raman spectra in the absence of undesired photochemistry and resonance enhancement. These investigations provide new information on the arrangement of the conformational energy surface in myoglobin and bacteriorhodopsin, pressure effects on protein dynamics and on the molecular structure of bacteriorhodopsin activation. %%% The dynamics structures which proteins maintain to perform biological functions are distinguished by changes in energy and volume from the unfolded polypeptide chain. Site-selective spectroscopic studies at variable temperature and pressure provide insight into the relative energy scales of molecular interactions in the stabilization of the biologically active molecule. Vibrational marker bands are used to monitor structural changes and motions in myoglobin and bacteriorhodopsin and correlate them with protein function. Since proteins share similarities in the thermodynamic, structural and dynamic properties with many disordered systems such as glasses, new insights from this research will have an impact on models for disorder and complexity in other fields of science. ***