Structure and stability of 3-alpha vs alpha/beta folds

3-α 与 α/β 折叠的结构和稳定性

• 批准号: 6621272
• 负责人: JOHN ORBAN
• 金额: $ 21.03万
• 依托单位: UNIVERSITY OF MD BIOTECHNOLOGY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6621272
• 关键词: bacterial proteins; bioenergetics; circular dichroism; conformation; gene rearrangement; genetic screening; immunoglobulin G; nuclear magnetic resonance spectroscopy; protein binding; protein folding; protein protein interaction; protein sequence; protein structure function; thermodynamics

DESCRIPTION (provided by applicant): The major difficulty in deciphering the protein folding code is that folding information is diffuse. The aim of this proposal is to better understand how amino acid sequence specifies unique tertiary folds by reducing the folding problem to those amino acids which contain the most information toward specifying one fold versus another. To do this, Dr. Orban proposes to generate and study pairs of proteins with high sequence identity but different tertiary structures. He will study switching between alpha/beta structure and three a-helix bundle structure (3-a) as a function of amino acid sequence and characterize the energy separating the two conformations by a variety of biophysical methods. The IgG-binding domains of streptococcal protein G (GB) and staphylococcal protein A (AB) will be used as one pair. The albumin binding domain of protein G (GA) and GB will be used as the second pair. All three domains are of similar size (45-58 amino acids). AB and GA have 3-alpha folds and GB has an alpha/beta fold. Phage display selection methods will be used to induce a conformational switch between the 3-a structure and the alpha/beta structure, while maintaining the highest practicable level of sequence identity. The PI will then use the thermodynamic linkage between folding and IgG- or albumin-binding to quantitate the folding information content of each amino acid which differs in homologous pairs. A variety of biophysical techniques including, multidimensional NMR, will be used to explore structural and energetic properties of the sequence space between the homologous protein pairs. More complete knowledge concerning how primary sequence determines stable, unique protein folds should greatly advance the fields of protein engineering, protein structure prediction and de novo protein design. There also may be applications of this technology to create molecular switches based on the property of a protein to change conformations in response to a subtle external stimulus.

描述（由申请人提供）：破译该信息的主要困难 蛋白质折叠密码是折叠信息是弥散的。此举的目的 建议是为了更好地理解氨基酸序列如何指定独特的 通过减少那些氨基酸的折叠问题来实现三级折叠 包含有关指定一种折叠与另一种折叠的最多信息。要做的事 为此，Orban 博士建议生成并研究具有高 序列相同但三级结构不同。他将研究切换 α/β结构和三个a-螺旋束结构(3-a)之间作为 氨基酸序列的功能并表征分隔两者的能量 通过多种生物物理方法进行构象。 IgG 结合域 链球菌蛋白 G (GB) 和葡萄球菌蛋白 A (AB) 将用作 一对。蛋白 G (GA) 和 GB 的白蛋白结合域将用作 第二对。所有三个结构域大小相似（45-58 个氨基酸）。 AB GA 具有 3-α 折叠，GB 具有 α/β 折叠。噬菌体展示 选择方法将用于诱导之间的构象转换 3-a结构和alpha/beta结构，同时保持最高 序列同一性的可行水平。然后 PI 将使用热力学 折叠与 IgG 或白蛋白结合之间的联系以定量折叠 同源对中每个氨基酸的信息含量不同。一个 将使用多种生物物理技术，包括多维核磁共振 探索序列空间之间的结构和能量特性 同源蛋白质对。关于如何初级的更完整的知识 序列决定了稳定、独特的蛋白质折叠应该大大推进 蛋白质工程、蛋白质结构预测和从头蛋白质领域 设计。该技术还可能应用于创建分子 根据蛋白质的特性进行开关以改变构象以响应 受到微妙的外部刺激。