Identification and characterization of the c-type cytochrome biogenesis apparatus of trypanosomes and the Euglenozoa

锥虫和裸虫c型细胞色素生物发生装置的鉴定和表征

• 批准号: BB/D019753/1
• 负责人: James Allen
• 金额: $ 70.18万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FD019753%2F1
• 关键词: Identification; characterization; type; cytochrome; biogenesis

Proteins are a major component of all living cells. They are nature's molecular machines and include enzymes, natural catalysts of chemical reactions. In addition to the basic amino acid building blocks, one-third of all proteins contain one or more metal ions (e.g. iron, zinc, copper), found singly, in metal clusters, or bound within a larger molecule and then to the protein. These metals in proteins provide excellent and elegantly tuned centres for nature to catalyse diverse chemical reactions; the reactions they facilitate are crucial for the life of all organisms. Respiration is the fundamental cellular process by which the fuel organisms consume (i.e. food) reacts with the oxygen they take in (e.g. by breathing) to produce the energy their cells need in a biologically useful form. An essential protein for respiration is called cytochrome c; it contains the molecule heme, which has an iron atom bound at its centre. Heme is the pigment that carries oxygen around our bodies when bound to the blood protein hemoglobin. However, unlike in hemoglobin, the heme in cytochrome c is attached permanently to the protein through (normally) two covalent bonds. Remarkably, at least three different systems have evolved in different types of organisms to accomplish this unusual and chemically difficult covalent heme attachment reaction. Understanding how these systems work and why different ones have evolved is a problem with wide ranging implications. As a consequence of some experiments I did on cytochrome c assembly in bacteria, I began to consider a family of single-celled organisms called trypanosomes. These are parasites of humans, animals and insects and cause fatal insect-bite transmitted diseases including African sleeping sickness, Chagas disease and Leishmaniasis, which threaten millions of people. Trypanosome cells contain cytochrome c which is special, because the heme is, uniquely, attached to the protein through only one covalent bond, rather than the usual two; this cytochrome c is required for the growth and survival of the cells. Recently, the genomes of six trypanosome species have been analysed. A genome is the blueprint of a species encoded by its DNA; it tells us all the proteins that the organism can make. Very surprisingly, the trypanosome genomes contain none of the proteins associated with the formation of cytochrome c in any other organisms. My project will be to answer questions related to these intriguing observations, principally: (i) What is the novel, completely unknown, system for making cytochrome c in these organisms? and (ii) How does the system work? I will use a wide range of experimental methods to address these questions. This work will be undertaken at the University of Oxford, using the world-class facilities for trypanosome research at the Dunn School of Pathology and for cytochrome research in the Department of Biochemistry. This exceptional conjunction of facilities makes Oxford a centre of excellence for this project. The discovery and characterization of a completely novel type of cytochrome c biogenesis system in the trypanosomes will be important. Fundamentally, it is necessary to establish how living cells carry out the individual processes they need for survival as scientists strive to understand how whole cells (and whole organisms) function. The novel means of cytochrome c synthesis used by the trypanosomes will also provide information about the uncertain evolutionary development of these specialized organisms, which is critical for understanding their biology. More specifically, cytochrome c formation in these infectious species is clearly distinct from that in mammals and so is a possible target for therapeutic drugs for humans and animals.

蛋白质是所有活细胞的主要组成部分。它们是自然界的分子机器，包括酶，化学反应的天然催化剂。除了基本的氨基酸结构单元，三分之一的蛋白质含有一个或多个金属离子（如铁，锌，铜），单独存在，金属簇，或结合在一个更大的分子，然后蛋白质。蛋白质中的这些金属为自然界提供了极好的和优雅的调节中心，以催化各种化学反应;它们促进的反应对所有生物体的生命至关重要。呼吸是基本的细胞过程，生物体消耗的燃料（即食物）与它们吸入的氧气（例如通过呼吸）反应，以生物学上有用的形式产生细胞所需的能量。一种呼吸所必需的蛋白质叫做细胞色素c，它含有血红素分子，血红素分子的中心有一个铁原子。血红素是一种色素，当与血液蛋白血红蛋白结合时，它将氧气带到我们的身体周围。然而，与血红蛋白不同的是，细胞色素c中的血红素通过（通常）两个共价键永久地附着在蛋白质上。值得注意的是，至少有三种不同的系统已经在不同类型的生物体中进化，以完成这种不寻常的和化学上困难的共价血红素附着反应。了解这些系统如何工作以及为什么不同的系统会进化是一个具有广泛影响的问题。由于我做了一些关于细胞色素c在细菌中组装的实验，我开始考虑一个被称为锥虫的单细胞生物家族。这些是人类、动物和昆虫的寄生虫，引起致命的昆虫叮咬传播疾病，包括非洲昏睡病、恰加斯病和利什曼病，威胁着数百万人。锥虫细胞含有细胞色素c，这是特殊的，因为血红素是唯一的，通过一个共价键连接到蛋白质，而不是通常的两个;这种细胞色素c是细胞生长和生存所必需的。最近，六个锥虫物种的基因组进行了分析。基因组是由DNA编码的物种蓝图;它告诉我们生物体可以制造的所有蛋白质。非常令人惊讶的是，锥虫基因组不包含任何其他生物中与细胞色素c形成相关的蛋白质。我的项目将是回答与这些有趣的观察有关的问题，主要是：（i）在这些生物体中制造细胞色素c的新颖的、完全未知的系统是什么？及（ii）该制度如何运作？我将使用广泛的实验方法来解决这些问题。这项工作将在牛津大学进行，利用邓恩病理学院的锥虫研究和生物化学系的细胞色素研究的世界一流设施。这种特殊的设施结合使牛津成为该项目的卓越中心。在锥虫中发现和表征一种全新类型的细胞色素c生物合成系统将是重要的。从根本上说，有必要确定活细胞如何进行生存所需的个体过程，因为科学家们正在努力了解整个细胞（和整个生物体）的功能。锥虫所使用的细胞色素c合成的新方法也将提供有关这些专门生物体的不确定进化发展的信息，这对于理解它们的生物学至关重要。更具体地说，这些感染性物种中的细胞色素c形成明显不同于哺乳动物中的细胞色素c形成，因此是人类和动物治疗药物的可能靶点。

项目成果

Heme conjugated magnetic beads to isolate heme-binding proteins from complex mixtures.

血红素缀合磁珠可从复杂混合物中分离血红素结合蛋白。

• DOI: 10.1016/j.pep.2010.10.001
• 发表时间: 2011
• 期刊: Protein expression and purification
• 影响因子: 1.6
• 作者: Jones R

A pivotal heme-transfer reaction intermediate in cytochrome c biogenesis.

• DOI: 10.1074/jbc.m111.313692
• 发表时间: 2012-01-20
• 期刊: The Journal of biological chemistry
• 作者: Mavridou DA;Stevens JM;Mönkemeyer L;Daltrop O;di Gleria K;Kessler BM;Ferguson SJ;Allen JW
• 通讯作者: Allen JW