THERMODYNAMIC AND KINETIC STUDIES OF PROTEIN STRUCTURE AND ENZYMIC MECHANISMS

蛋白质结构和酶机制的热力学和动力学研究

• 批准号: 5201928
• 负责人: P MC PHIE
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/5201928
• 关键词: chemical kinetics; circular dichroism; enzyme mechanism; fluorescence spectrometry; hormone receptor; pepsin; pepsinogens; protein folding; protein sequence; protein structure; stop flow technique; sulfotransferase; temperature jump; thermodynamics; thyroid hormones; tryptophan synthase; ultraviolet spectrometry

This laboratory is engaged in studies on protein structure and the mechanism of protein folding. The main subject of research is swine pepsinogen, a monomeric protein of molecular weight = 39,630, which is stable at pH's between 6 and 8.5. Below pH 6 pepsinogen activates itself by proteolytic loss of it's first 44 amino acids, to produce an enzymatically active protein, pepsin. Pepsin is stable only at pH's below 6. Pepsin and pepsinogen are unfolded by exposure to high pH, temperature or concentrations of denaturants, such as urea. However, unfolded pepsinogen can refold to its normal structure, when returned to native conditions, whereas pepsin cannot. I am interested in the mechanism of this refolding reaction and how the difference in sequence influences the refolding of the two proteins. We have used rapid kinetic techniques, (stopped-flow and T-jump), to detect partly folded intermediate forms in the folding reaction; their structures have been partially determined and the nature of the chemical reactions which separate them from the native and unfolded forms investigated. Techniques such as ultra-violet absorbance, circular dichroic and fluorescence spectroscopies, together with chemical modification and peptide chemistry, to characterize the structures of native and unfolded forms of these and other proteins, including tryptophan synthase, human nuclear thyroid hormone receptor and sulphotransferase enzymes.

这个实验室从事蛋白质结构和蛋白质的研究