RUI: Novel Heme Chemistry of Cytochrome c'

RUI：细胞色素 c 的新型血红素化学

• 批准号: 1411963
• 负责人: Colin Andrew
• 金额: $ 29.82万
• 依托单位: Eastern Oregon University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1411963&HistoricalAwards=false
• 关键词: RUI; Novel; Heme; Chemistry; Cytochrome

In many processes vital for life (e.g. respiration, gas sensing/signaling, and toxicity defense) heme proteins must bind a specific diatomic gas, e.g. oxygen (O2), carbon monoxide (CO), or nitric oxide (NO). To modulate heme reactivity (and achieve a selective gas response), proteins utilize the structural and chemical properties of the heme pocket environments. A major goal of this project is to investigate how the spatial environments of heme iron sites can dramatically affect their reactivity with gases. This knowledge is important for understanding fundamental biochemical reactions in animals, plants, and bacteria, as well as for the rational design of heme-gas sensors with unique properties. Undergraduate research is an integral part of the project, providing students and local high-school teachers with stimulating experiences and motivation for future scientific endeavors.The project will focus on the novel heme reactivity of bacterial cytochromes c' in which steric constraints significantly disfavor the distal coordination of O2, CO, and NO, while promoting an unusual distal to proximal heme-NO conversion. The coordination of NO at both heme faces (distal and proximal) represents a new type of heme protein reactivity that may be relevant to the proposed NO-binding function(s) of cytochromes c', as well as to NO-selective responses in gas-sensing proteins. By characterizing distal pocket variants of Alcaligenes xylosoxidans cytochrome c' (AXCP), as well as other cytochromes c', the overall goal is to define the connection between distal steric constraints, structural perturbations, and heme reactivity, including distal vs proximal NO coordination. A "loaded spring" hypothesis will be tested in which steric clashes between the crowded distal pocket and diatomic gas (XO) ligands lead to structurally perturbed high-energy heme-XO complexes with altered reactivity. The project will utilize spectroscopy (UV-visible absorption, resonance Raman, and Electron Paramagnetic Resonance), kinetics (stopped-flow and flash photolysis) and other techniques (X-ray crystallography and potentiometry) to study wild-type and variant cytochrome c' reactivity as function of distal steric bulk and gas identity. Undergraduates and high school teachers will receive training in these techniques and be involved in interpreting the results.

在许多对生命至关重要的过程中（例如呼吸、气体传感/信号传导和毒性防御），血红素蛋白必须结合特定的双原子气体，例如氧气（O2）、一氧化碳（CO）或一氧化氮（NO）。为了调节血红素反应性（并实现选择性气体反应），蛋白质利用血红素口袋环境的结构和化学性质。该项目的一个主要目标是研究血红素铁位点的空间环境如何显著影响它们与气体的反应性。这些知识对于理解动物、植物和细菌中的基本生化反应以及具有独特性质的血红素气体传感器的合理设计是重要的。本科生研究是该项目的一个组成部分，为学生和当地高中教师提供刺激的经验和未来的科学努力的动机。该项目将集中在细菌细胞色素c'的新颖血红素反应性，其中空间限制显着不利于O2，CO和NO的远端协调，同时促进不寻常的远端到近端血红素-NO转换。在两个血红素面（远端和近端）的NO的协调代表了一种新型的血红素蛋白反应性，其可能与所提出的细胞色素c '的NO结合功能以及气敏蛋白中的NO选择性反应有关。通过表征木糖氧化产碱菌细胞色素c'（AXCP）以及其他细胞色素c'的远端口袋变体，总体目标是定义远端空间约束、结构扰动和血红素反应性之间的联系，包括远端与近端NO协调。一个“加载弹簧”的假设将进行测试，其中拥挤的远端口袋和双原子气体（XO）配体之间的空间冲突导致结构扰动的高能量血红素-XO复合物的反应性改变。该项目将利用光谱学（紫外-可见吸收、共振拉曼和电子顺磁共振）、动力学（停流和闪光光解）和其他技术（X射线晶体学和电位测定法）研究野生型和变异细胞色素c'的反应性，作为远端空间体积和气体特性的函数。大学生和高中教师将接受这些技术的培训，并参与解释结果。

项目成果

Hydroxylamine Complexes of Cytochrome c′ : Influence of Heme Iron Redox State on Kinetic and Spectroscopic Properties

细胞色素 c 的羟胺配合物：血红素铁氧化还原状态对动力学和光谱性质的影响

• DOI: 10.1021/acs.inorgchem.0c01925
• 发表时间: 2020
• 期刊: Inorganic Chemistry
• 影响因子: 4.6
• 作者: Brown, Brianna N.;Robinson, Kelsey J.;Durfee, Quentin C.;Kekilli, Demet;Hough, Michael A.;Andrew, Colin R.
• 通讯作者: Andrew, Colin R.