Structural Studies on Heme Enzymes and Proteins

血红素酶和蛋白质的结构研究

• 批准号: 9807798
• 负责人: Thomas Poulos
• 金额: $ 48万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-15 至 2003-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9807798&HistoricalAwards=false
• 关键词: Structural; Studies; Heme; Enzymes; Proteins; Structural; Studies; Heme; Enzymes; Proteins

Poulos9807798The purpose of this project is to use primarily x-ray crystallography to study structure-function relationships in heme containing enzymes and proteins. So far the focus has been on peroxidases. Peroxidases participate in a wide range of biological processes requiring oxidatiion of molecules and removal of peroxides. Several peroxidase structures have been solved so the project will now move into a more detailed analysis of function. In particular, the focus will be on chloroperoxidase (CPO), the most diverse of the known heme enzyme catalysts. The goal is to couple mutagenesis, molecular modeling, and crystallography in order to understand how CPO catallyzes stereoselective epoxidation, sulfoxidtion, and hydrogen abstraction reactions. In addition, the structure of the novel heme catalyst, heme oxygenase, will be determined. Recently, it has been found that some peroxidase crystals when frozen in liquid nitrogen diffract to beyond 1A resolution using synchrotron radiation. This provides a rare opprtunity for determining the structure of moderately large glycoproteins at true atomic resolution. Studies also will be initiated on novel heme proteins that operate as biological sensors and transcription factors. A transcriptional regulatory protein that senses carbon monoxide will be a particular focus.The enzymes under investigation catalyze a variety of biologically important oxidations. A common theme is the presence of a heme prosthetic group. The remarkable feature in these proteins is the wide range of functions even though the hene group is exactly the same. These functions include oxygen carriers (hemoglobin and myoglobin), electron transfer proteins (cytochromes), and the enzymes under investigation in this project which catalyze bond making and breaking reactions. Some heme enzymes catalyze reactions that are important for degrading toxic environmental pollutants as well as stereospecific oxidations. Such reactions are quite important in various industrial processes where the need for stereoselectivity is high. Engineeering enzymes for this purpose is an area of considerable interest in thr synthesis of rare and expensive intermediates used in the production of important organic molecules. In recent years, a number of these important enzymes have been cloned and expressed in bacterial hosts. This opens the way for engineering these enzymes to tailor them for specific functions. However, before such engineering efforts can move forward, it is necessary to determine the three dimensional structural. Achieving this goal of structue determination using x-ray crystallography is the primary focus of this research.

POULOS9807798该项目的目的是主要使用X射线晶体学来研究含有酶和蛋白质血红素的结构 - 功能关系。 到目前为止，重点一直放在过氧化物酶上。 过氧化物酶参与需要分子氧化和去除过氧化物的广泛生物学过程。 已经解决了几种过氧化物酶结构，因此该项目现在将进入更详细的功能分析。 特别是，焦点将放在氯哌氧化酶（CPO）上，这是已知的血红素酶催化剂中最多样化的。 目的是将诱变，分子建模和晶体学造影，以了解CPO如何催化立体选择性环氧化，磺化和氢抽象反应。 另外，将确定新型血红素催化剂，血红素氧酶的结构。 最近，已经发现，使用同步加速器辐射在液氮衍射中冷冻至1A分辨率的某些过氧化物酶晶体。 这提供了一种罕见的Opprtunity，用于确定真原子分辨率中适中大糖蛋白的结构。 研究还将启动，以作为生物传感器和转录因子作用的新型血红素蛋白。 感官一氧化碳的转录调节蛋白将是一个特殊的焦点。所研究的酶催化了多种生物学上重要的氧化。 一个共同的主题是血红素假肢的存在。 这些蛋白质中的显着特征是，即使Hene组完全相同，功能也很广。 这些功能包括氧载体（血红蛋白和肌红蛋白），电子转移蛋白（细胞色素）以及该项目中正在研究的酶，这些酶催化键合成和破坏反应。 一些血红素酶催化对降解有毒环境污染物以及立体特异性氧化很重要的反应。 在对立体选择性需求很高的各种工业过程中，这种反应非常重要。 为此目的，引擎酶是对重要有机分子生产中稀有且昂贵的中间体的兴趣非常感兴趣的领域。 近年来，许多这些重要酶已克隆并在细菌宿主中表达。 这为这些酶的设计开辟了道路，以根据特定功能调整它们。 但是，在进行此类工程工作之前，有必要确定三维结构。 使用X射线晶体学实现结构确定的目标是这项研究的主要重点。