RAMAN STUDIES OF PORPHYRINS/PROTEIN MAQUETTES/PROTEINS

研究的目标是表征结构，电子， 和振动，性质的四吡咯大环在各种 环境，包括溶液、血红素蛋白、血红素蛋白模型 （小的合成蛋白质）和超分子组装（合成的 纳米结构）。 主要的研究工具是共振拉曼 (RR)光谱，虽然紫外-可见，红外（IR），和电子 顺磁共振（EPR）光谱;电化学技术; 振动分析方法也起着重要的作用。长期 目的是将环的物理性质与它们的 功能特性（配体结合和转运，电子 能量转移，催化）在合成和天然 proteins.具体目标如下：（1）低频振动 将获得光谱并分配给各种五个和六个， 配位卟啉和氢化卟啉。最佳力场将是 开发的环的平面外变形。这些力 字段将明确包括组氨酸作为轴向配体。(2)RR 将获得一系列远端位点肌红蛋白突变体的光谱 其X-射线晶体结构和配体结合动力学已经很好地 表征了RR数据将在完整的 血红素（轴向配体）低频振动模型 单位，以开发可靠的频率/结构/配体结合 亲和相关性突变体的RR数据也将用于 进一步细化的力场的平面外模式的 血红素/轴向配体单元。 这个力场应该比 一个是从模型复合体单独发展起来的， 在分子动力学模拟中血红素运动的精确建模。 (3)将获得一系列小分子（62个氨基酸）的RR光谱 合成的单血红素和二血红素结合肽。这些数据将用于 评估血红素的结构如何影响它们的氧化还原化学。这 这些信息将成为未来合成蛋白质设计的基准 旨在精确控制血红素的氧化还原性质。（四） 光学，RR和EPR光谱将获得各种新的， 共价连接的卟啉组装体。这些数据将用于 确定组件中的环的几何布置如何 影响大环之间的电子通讯。

The goals of the research are to characterize the structural, electronic, and vibrational, properties of tetrapyrrolic macrocycles in various environments including solutions, heme proteins, heme protein maquettes (small synthetic proteins), and supramolecuIar assemblies (synthetic nanostructures). The principal investigative tool is resonance Raman (RR) spectroscopy, although Uv-Vis, infrared (IR), and electron paramagnetic resonance (EPR) spectroscopies; electrochemical techniques; and vibrational analysis methods also play important roles. The long-term objective is to relate the physical properties of the rings to the their functional characteristics (ligand binding and transport, electron transfer, energy transfer, catalysis) in both synthetic and natural proteins. The specific aims are as follows: (l) Low-frequency vibrational spectra will be obtained and assigned for various five- and six- coordinate porphyrins and hydroporphyrins. Optimum force fields will be developed for the out-of-plane deformations of the rings. These force fields will explicitly include histidine as an axial ligand. (2) RR spectra will be obtained for a series of distal-site myoglobin mutants whose X-ray crystal structures and ligand-binding kinetics have been well characterized. The RR data will be assessed in the context of a complete vibrational model for the low-frequency modes of the heme(axial-ligand unit in order to develop reliable frequency/structure/ligand-binding affinity correlations. The RR data for the mutants will also be used for further refinement of the force field for the out-of-plane modes of the heme/axial-ligand unit. This force field should be more reliable than one developed from model complexes alone and should facilitate more accurate modeling of the heme motions in molecular dynamics simulations. (3) RR spectra will be obtained for a series of small (62 amino acids) synthetic mono- and diheme binding peptides. These data will be used to assess how the structure of the hemes affects their redox chemistry. This information will serve as a benchmark for future synthetic protein design aimed at precise control of the redox properties of the hemes. (4) Optical, RR, and EPR spectra will be obtained for a variety of novel, covalently linked porphyrinic assemblies. These data will be used to determine how the geometrical arrangement of the rings in the assembly affects the electronic communication between the macrocycles.