The Fluorescence of Indole, Tryptophan and Proteins

本研究的目的是了解局部环境对蛋白质中色氨酸残基荧光衰减的影响。利用脉冲纳秒荧光法研究了吲哚、3-甲基吲哚和色氨酸的荧光性质。荧光衰减数据与激发在各种波长将获得作为粘度和溶剂极性的函数。将进行实验以光选择差异溶剂化荧光团的亚群。数据将表示为荧光衰减相关光谱（DAS）和时间分辨发射光谱（TRES）。 为了预测激发波长和环境条件如粘度、温度和极性对激发态溶剂化过程的影响，将进行理论研究。类似的研究将用几种含色氨酸的蛋白质进行，包括PTS的酶I的突变形式、半乳糖阻遏物、髓鞘碱性蛋白和超硫硼同源结构域（UBX）。 这些实验旨在提供蛋白质中色氨酸残基与极性溶剂环境之间相互作用的信息，提供更详细的蛋白质结构与荧光之间关系的信息，并解释蛋白质构象变化或与其他分子相互作用时观察到的变化。蛋白质的功能包括催化活性和调节。这些事件涉及通过色氨酸荧光可观察到的构象变化。色氨酸荧光对蛋白质构象变化的敏感性的起源仍然是难以捉摸的。这些研究的目的是利用纳秒时间分辨荧光方法来了解激发态溶剂化和电荷对蛋白质中色氨酸荧光的影响。这一工作将促进荧光光谱在蛋白质功能和结构研究中的应用。

The goal of this research is to understand the influence of the local environment on the fluorescence decay of tryptophan residues in proteins. The fluorescence of indole, 3-methyl indole and tryptophan will be studied with the aid of pulse nanosecond fluorescence methods. Fluorescence decay data with excitation at various wavelengths will be obtained as a function of viscosity and solvent polarity. Experiments will be done to photoselect subpopulations of differentially solvated fluorophores. The data will be represented as fluorescence decay associated spectra (DAS) and time-resolved emission spectra (TRES). Theoretical studies will be done in order to predict the influence of excitation wavelength and environmental conditions such as viscosity, temperature and polarity on excited-state solvation processes. Similar studies will be done with several single tryptophan containing proteins including mutant forms of Enzyme I of the PTS, the galactose repressor, myelin basic protein and the ultrathioborax homeodomain (UBX). These experiments are designed to provide information about the mutual interaction between tryptophan residues in proteins and the polar solvent environment to provide more detailed information about the relation between protein structure and fluorescence and to explain the changes observed when proteins exhibit conformational changes or interact with other molecules.The functions of proteins include catalytic activity and regulation. These events involve conformational changes observable by tryptophan fluorescence. A clear understanding of the origin of the sensitivity of tryptophan fluorescence to conformational changes of proteins remains elusive. The aim of these studies is to utilize nanosecond time-resolved fluorescence methods to understand the influence of excited-state solvation and charges on the fluorescence of tryptophan in proteins. This work will enhance the application of fluorescence spectroscopy to studies of function and structure of proteins.