Mapping the acylated proteome: a chemical genetic approach

随着几个重要的基因组计划的完成，如人类基因组计划，我们现在有了描述细胞产生的蛋白质的基本代码，这些蛋白质执行生命的基本过程。然而，这只是我们全面了解细胞功能的开始：研究的重点现在已经转移到揭示细胞中每种蛋白质的作用，以及何时何地进行。更复杂的是，蛋白质的结构在最初产生后（从遗传密码中“翻译”出来）经常被其他称为酶的蛋白质修改，这一过程被称为“翻译后修饰”。这些修饰在细胞中具有至关重要的功能；例如，它们参与了我们对疾病的免疫反应和病毒感染的机制，缺陷修饰与癌症等疾病有关。针对真菌和寄生虫（例如导致疟疾的单细胞寄生虫恶性疟原虫）等致病生物的翻译后酶的药物正在开发中，可能对我们控制这些疾病的能力产生重大影响。然而，由于细胞中数千种不同蛋白质（被称为“蛋白质组”）的复杂性，很难确定哪些蛋白质被修饰，以及这种修饰对蛋白质功能的影响。鉴定修饰的蛋白质组是理解翻译后修饰作用的关键一步，也是发现上述药物在细胞中可能产生的作用（和副作用）的关键一步。拟议的研究旨在通过整合有机化学的最新发现和尖端的全蛋白质组分析来解决这一挑战。我们的目标是利用细胞自身的酶，在蛋白质中引入一种化学“标签”，通过一种被称为“酰化”的过程进行修饰。这些标签是为了不破坏细胞的正常功能而设计的，我们可以非常有选择性地“捕获”并用专门设计的试剂纯化标记的酰基蛋白。这将使我们能够极大地提高全蛋白质组分析对酰基修饰的敏感性，揭示迄今为止尚未确定的酰基蛋白，并开辟新的研究途径，研究酰基化在细胞中的作用。后来，我们打算利用这种标签和捕获方法来分析药物对单细胞寄生虫中修饰的蛋白质组的影响，甚至使我们能够在显微镜下看到修饰的蛋白质在细胞内移动。这项工作将把伦敦帝国理工学院的化学家和约克大学的生物学家聚集在一起，进行“跨学科”合作/也就是说，在化学和生物学的传统学科之间的接口。

With the completion of several important genome projects, such as the Human Genome Project, we now have the basic code describing the proteins made by cells which carry out the essential processes of life. However, this is only the beginning of our journey towards fully understanding how cells function: the focus of research has now moved to unravelling the role of each protein in a cell, and when and where it is carried out. To further complicate the story, the structure of a protein is frequently modified after its initial creation (its 'translation' from the genetic code) by other proteins called enzymes, a process termed 'post-translational modification'. These modifications can have critically important functions in the cell; for example, they are involved in our immune response to disease and the mechanism of infection by viruses, and defective modification is implicated in diseases such as cancer. Drugs which target the post-translational enzymes in pathogenic organisms such as fungi and parasites (for example, Plasmodium falciparum, the single-celled parasite which causes malaria) are under development, and could make a major impact on our ability to control these diseases. However, due to the complexity of the total set of thousands of different proteins in a cell (dubbed the 'proteome'), it has proven difficult to identify which proteins are modified, and what effect the modification has on a protein's function. Identifying the modified proteome is a key step towards understanding the role of post-translational modification, and to discover what effects (and side-effects) the drugs mentioned above may have in the cell. The proposed research aims to address this challenge by integrating recent discoveries in organic chemistry with cutting-edge whole-proteome analysis. We aim to exploit the cell's own enzymes to introduce a chemical 'tag' into proteins which are modified by a process termed 'acylation'. The tags are designed so as not to disrupt the cell's normal function, and we can very selectively 'capture' and purify the tagged acyl proteins with specially designed reagents. This will allow us to hugely increase the sensitivity of whole-proteome analysis towards acyl modifications, revealing hitherto unidentified acyl proteins and opening up new lines of investigation into the role of acylation in cells. Later, we intend to exploit this tag and capture methodology to analyse the effect of drugs on the modified proteome in single-celled parasites, and even to enable us to see modified proteins under a microscope as they move around the cell. This work will bring together chemists at Imperial College London and biologists at the University of York in an 'interdisciplinary' collaboration / that is, at the interface between the traditional disciplines of Chemistry and Biology.