Form and function in the ESX-1 secretion system; elucidation of mechanism and structural determinants of bacterial virulence.

ESX-1 分泌系统的形式和功能；

基本信息

批准号：
BB/H007571/1
负责人：
William Hunter
金额：
$ 80.51万
依托单位：
University of Dundee
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FH007571%2F1
关键词：
Form function ESX secretion system

项目摘要

Almost all bacteria cause disease by producing toxins that they secrete into the host. Many of these toxins are protein molecules, and the bacterium has specialised machines in the cell membrane that allows the controlled passage of these toxins to the outside. We are working on one of these machines; the recently discovered ESX-1 system seeking to understand a central aspect of microbiology, namely how protein secretion machines work. This ESX-1 system has been shown to be essential for the virulence of important pathogens (M. tuberculosis, B. anthracis and S. aureus) and so there is a biomedical and agricultural aspect to this basic research. We have identified that the Staphylococcus aureus ESX-1 appears to be the most tractable for structure-function studies. S. aureus is a commensal Gram positive bacterium responsible for a number of illnesses in humans and animals that range from minor skin infections, such as pimples and abscesses, Toxic shock syndrome (TSS) through to septicaemia and mastitis in dairy herds and pigs. However, it is most widely known as a major cause of hospital acquired infections, and is a frequent cause of post-surgical wound infections. This situation is exacerbated by the fact that some strains of S. aureus are resistant to many antibiotics (e.g. Methicillin Resistant Staphylococcus aureus), making it a severe and difficult to treat problem. The number of deaths attributed to S. aureus infection is comparable to that attributed to acquired immune deficiency syndrome. An understanding, at the molecular level, of S. aureus biology and pathogenesis is essential if we are to design new treatments to prevent or cure infection. The ESX-1 transport system drives the secretion of at least three different proteins from S. aureus, and it is known that when this system is inactivated S. aureus shows a dramatic reduction in its ability to cause infection. We seek knowledge of the architecture and function of this distinctive bacterial secretion machine and identification of its cargo. The ESX-1 system consists of 5-8 different protein components. We will investigate how these proteins interact to assemble the secretion machine, and the molecular basis for how the machine works. To attain this goal we must derive the structure and function of each component, elucidate how the components interact and quantify the association, determine the molecular basis for cargo recognition, and the generation of the motive force. We have already made significant progress with six of these proteins cloned, expressed and purified and two crystallised. We will exploit single crystal X-ray diffraction methods to derive accurate molecular structures and a battery of biophysical techniques to characterise the protein-protein interactions. Knowing the structures of the protein components and how they interact with each other is important because this might, in the longer term, lay the foundation for studies directed to the design or discovery of compounds that will prevent these proteins from working with each other or prevent the motive force from being used to secrete out the proteins that establish and prolong infection. Information on proteins that are secreted and of the structures found on the surface of the bacterium may also provide opportunities for vaccine design.

几乎所有细菌都通过产生分泌到宿主体内的毒素来引起疾病。这些毒素中有许多是蛋白质分子，细菌的细胞膜上有专门的机器，可以控制这些毒素到外面的通道。我们正在研究其中一台机器；最近发现的 ESX-1 系统试图了解微生物学的一个核心方面，即蛋白质分泌机器如何工作。该 ESX-1 系统已被证明对于重要病原体（结核分枝杆菌、炭疽杆菌和金黄色葡萄球菌）的毒力至关重要，因此这项基础研究具有生物医学和农业方面的意义。我们发现金黄色葡萄球菌 ESX-1 似乎最适合结构功能研究。金黄色葡萄球菌是一种革兰氏阳性共生细菌，可引起人类和动物的多种疾病，包括丘疹和脓肿等轻微皮肤感染、中毒性休克综合征 (TSS) 以及奶牛群和猪的败血症和乳腺炎。然而，它被广泛认为是医院获得性感染的主要原因，并且是术后伤口感染的常见原因。由于某些金黄色葡萄球菌菌株对许多抗生素（例如耐甲氧西林金黄色葡萄球菌）具有抗药性，因此这种情况更加严重，使其成为一个严重且难以治疗的问题。金黄色葡萄球菌感染导致的死亡人数与获得性免疫缺陷综合征导致的死亡人数相当。如果我们要设计新的治疗方法来预防或治愈感染，那么在分子水平上了解金黄色葡萄球菌的生物学和发病机制至关重要。 ESX-1 转运系统驱动金黄色葡萄球菌分泌至少三种不同的蛋白质，并且已知当该系统失活时，金黄色葡萄球菌引起感染的能力显着降低。我们寻求了解这种独特的细菌分泌机器的结构和功能以及其货物的识别。 ESX-1 系统由 5-8 种不同的蛋白质成分组成。我们将研究这些蛋白质如何相互作用来组装分泌机器，以及该机器如何工作的分子基础。为了实现这一目标，我们必须推导每个组件的结构和功能，阐明组件如何相互作用并量化关联，确定货物识别的分子基础以及原动力的产生。我们已经在其中六种蛋白质的克隆、表达和纯化以及两种蛋白质的结晶方面取得了重大进展。我们将利用单晶 X 射线衍射方法来推导准确的分子结构，并利用一系列生物物理技术来表征蛋白质-蛋白质相互作用。了解蛋白质成分的结构以及它们如何相互作用非常重要，因为从长远来看，这可能为设计或发现化合物的研究奠定基础，这些化合物将阻止这些蛋白质彼此相互作用或阻止用于分泌建立和延长感染的蛋白质的动力。有关细菌分泌的蛋白质和细菌表面结构的信息也可能为疫苗设计提供机会。

项目成果

期刊论文数量（6）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

EssC is a specificity determinant for Staphylococcus aureus type VII secretion.

EssC 是金黄色葡萄球菌 VII 型分泌的特异性决定因素。

DOI：
http://dx.10.1099/mic.0.000650
发表时间：
2018
期刊：
Microbiology (Reading, England)
影响因子：
0
作者：
Jäger F
通讯作者：
Jäger F

A membrane-depolarizing toxin substrate of the Staphylococcus aureus type VII secretion system mediates intraspecies competition.

金黄色葡萄球菌 VII 型分泌系统的膜去极化毒素底物介导种内竞争。

DOI：
http://dx.10.1073/pnas.2006110117
发表时间：
2020
期刊：
Proceedings of the National Academy of Sciences of the United States of America
影响因子：
11.1
作者：
Ulhuq FR
通讯作者：
Ulhuq FR

Heterogeneity in ess transcriptional organization and variable contribution of the Ess/Type VII protein secretion system to virulence across closely related Staphylocccus aureus strains.

ess 转录组织的异质性以及 Ess/VII 型蛋白分泌系统对密切相关的金黄色葡萄球菌菌株毒力的不同贡献。