THERMODYNAMICS OF PROTEIN DENATURATION

蛋白质变性的热力学

• 批准号: 6030285
• 负责人: DAVID W BOLEN
• 金额: $ 21.4万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-01 至 2003-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6030285
• 关键词: analytical method; bacterial proteins; calorimetry; chemical stability; chymotrypsin; cytochrome c; gel filtration chromatography; lysozyme; pancreatic ribonuclease; protein denaturation; protein structure function; thermodynamics

The denatured state of a protein is implicated in a number of disease states, and plays a functionally important role in such biologically important process as transport across membranes, protein degradation and protein folding. It is the long-term goal of this work to elucidate the thermodynamic properties of the denatured ensemble, and thereby understand how these properties relate to the compactness of the denatured state, and to the denaturation Gibbs energy changes used in assessing the stability of proteins. This project will focus on a class of proteins whose denatured ensembles continue to change their thermodynamic characters as a function of denaturant concentration. The "variable" thermodynamic behavior of the denatured ensembles of such proteins contrasts dramatically with the "fixed" behavior exhibited by proteins whose denatured ensembles do not change their thermodynamic properties as a function of denaturant. Potentiometric titrations of native and denatured ensembles, as well as proton uptake/release measurements, will be used to: (1) distinguish "variable" from "fixed" thermodynamic behavior of denatured ensembles, and (2) to provide a model-independent means of evaluating the Gibbs energy differences between native and/or denatured states of proteins with related sequences. Size exclusion chromatography will also be used, to correlate dimensional changes in a denatured ensemble with that ensemble's thermodynamic properties, as a function of denaturant concentration. Our ultimate aim is to provide a strong foundation for thermodynamic measurements of protein stability, a foundation that at present is weak or invalid for many proteins.

蛋白质的变性状态与许多疾病状态有关，并且在跨膜，蛋白质降解和蛋白质折叠等生物学重要过程中起功能重要的作用。 这项工作的长期目标是阐明变性合奏的热力学特性，从而了解这些特性如何与变性状态的紧凑性以及与评估蛋白质稳定性的变性Gibbs能量变化有关。 该项目将集中于一类蛋白质，其变性合奏继续改变其热力学特征，这是变性浓度的函数。 这种蛋白质的变性合奏的“可变”热力学行为与蛋白质表现出的“固定”行为形成鲜明对比，其变性的集合不会改变其热力学特性作为变性剂的函数。 天然和变性的合奏的电位滴定以及质子的吸收/释放测量将用于：（1）将“变量”与变性合奏的“固定”热力学行为区分开来，（2）提供与gibbs能量差异的模型依赖性方法与/或或脱粉的状态相关的蛋白质蛋白质的差异。 还将使用尺寸排除色谱法，以将变性合奏中的维数变化与该集合的热力学特性相关联，这是变性浓度的函数。 我们的最终目的是为蛋白质稳定性的热力学测量提供牢固的基础，这一基础目前对许多蛋白质而言是弱或无效的基础。