Peptide Conformation Studies with Vibrational Spectroscopy and Site Selective Isotopic Labeling

这个项目由化学部的实验物理化学项目资助，研究多肽构象、能量学以及蛋白质结构和折叠的动力学。大多数寡肽是非常灵活的，因此阻碍了传统的结构分析，特别是在一个结构正在转变为另一个结构的情况下，例如折叠。为了克服这些困难，凯德林将开展一项研究计划，将红外(IR)、拉曼、振动圆二色(VCD)和拉曼光学活性的解释，以及与时间相关的拉曼和红外光谱实验建立在坚实的基础上。为此，他将(A)使用同位素标记系统来给出振动光谱的可分辨的、特定位置的特征，以及(B)为在多肽中测量的振动光谱强度带形状开发更可靠的解释基础。实验工作将得到DFT增广的高斯98计算的辅助，以获得用于计算光谱建模的光谱参数。大多数实验和计算工作将集中在Beta-发夹和Beta-Sheet建模上。具有不同β转角稳定残基的不同长度的多肽将在热解折叠和重折叠时被研究。这项工作的总体目标是开发增强的结构生物学工具，包括实验和理论工具，并对折叠能量学有一个基本的了解，能够满足广泛的生物物理需求。这项研究将与学生和博士后研究助理一起进行。因此，他们将在当代生物物理化学快速发展的前沿领域之一获得技能和培训，为在我国经济的科学/技术部门深造或就业做准备。

This project, funded by the Experimental Physical Chemistry Program of the Chemistry Division, deals with peptide conformations, energetics, and dynamics of protein structure and folding. Most oligopeptides are quite flexible and thereby inhibit conventional structural analyses, especially under conditions where one structure is changing into another, such as folding. To overcome these difficulties Keiderling will conduct a research program to place the interpretation of infrared (IR), Raman, vibrational circular dichroism (VCD) and Raman optical activity, as well as time-dependent Raman and IR spectra experiments on a solid foundation. To this end he will (a) employ isotopically labeled systems to give the vibrational spectra resolved, site-specific character, and (b) develop a more reliable interpretative basis for the vibrational spectral intensity band shapes measured in peptides. The experimental efforts will be aided by DFT augmented Gaussian 98 calculations to obtain spectral parameters for computational modeling of the spectra. Most experimental and computational efforts will focus on beta-hairpin and beta-sheet modeling. Peptides of different lengths with various beta-turn stabilizing residues will be studied while thermally unfolded and refolded. The overall goal of the work is the development of enhanced structural biology tools, both experimental and theoretical, and obtain a basic understanding of folding energetics, capable of addressing broad biophysical needs. This research will be conducted with students and postdoctoral research associates. They will thereby acquire skills and training in one of the fast developing forefront areas of contemporary bio-physical chemistry, in preparation for advanced studies or employment in the scientific/technological sectors of our economy.