EVOLUTION OF REDOX REACTIVITY IN CYTOCHROME B

细胞色素 B 中氧化还原反应性的演变

• 批准号: 6294068
• 负责人: RACHAEL A KIPP
• 金额: $ 3.48万
• 依托单位: PRINCETON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6294068
• 关键词: biochemical evolution; chemical kinetics; chemical substitution; computer simulation; cytochrome b; flash photolysis; heme; intermolecular interaction; metalloporphyrins; model design /development; molecular dynamics; nuclear magnetic resonance spectroscopy; oxidation reduction reaction; peptide library; physical model; protein engineering; protein structure function; site directed mutagenesis; solvents; statistics /biometry; structural biology; thermodynamics

The redox potential sets the energy yield possible in metabolism, and is also a key determinant of the rate at which the redox reaction proceeds. Understanding the factors that govern redox reactivity represents a current frontier in structure-function relationships for electron transfer proteins. The heme protein cytochrome bw2 is used as a paradigm to study the co-evolution of redox potential and redox reactivity within a systematic library of variants. Function evolves by single or pair wise mutations of residues in the vicinity of the heme. Both thermodynamic potential (EO) and redox reactivity (self exchange and cross exchange rates) are measured. All possible variants (all 20 amino acids) at each position are cloned, and a simple color screen allows the mutants that have retained both structure and affinity for the b-type heme to be determined. The extrema are used as progenitors of the next generation of variants. Comparing the variation of redox potential with that of the kinetic reactivity (within the context of Marcus theory) in these mutants will give insights into the degree of evolutionary coupling between these two properties.

氧化还原电位设定代谢中可能的能量产量，并且也是氧化还原反应进行的速率的关键决定因素。了解的因素，支配氧化还原反应代表了目前的前沿电子转移蛋白质的结构与功能的关系。以血红素蛋白细胞色素bw 2为范式，研究系统变体库中氧化还原电位和氧化还原反应性的协同进化。功能通过血红素附近残基的单个或成对突变而进化。热力学势（EO）和氧化还原反应性（自交换和交叉交换率）的测量。克隆每个位置上所有可能的变体（所有20个氨基酸），并通过简单的彩色筛选确定保留了结构和对b型血红素亲和力的突变体。极值被用作下一代变体的祖先。比较这些突变体的氧化还原电位的变化与动力学反应性（马库斯理论的背景下）将深入了解这两个属性之间的进化耦合的程度。