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；

• 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

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.

几乎所有的细菌都是通过分泌毒素进入宿主体内而引起疾病的。这些毒素中的许多是蛋白质分子，细菌在细胞膜中有专门的机器，允许这些毒素受控地传递到外部。我们正在研究其中的一台机器;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系统已被证明对重要病原体的毒力至关重要（M.结核病，B. anthracis和S.金黄色葡萄球菌），因此这项基础研究涉及生物医学和农业方面。我们已经确定，金黄色葡萄球菌ESX-1似乎是最易处理的结构-功能研究。S.金黄色葡萄球菌是一种革兰氏阳性细菌，可引起人类和动物的多种疾病，从轻微的皮肤感染，如丘疹和脓疱，中毒性休克综合征（TSS）到奶牛群和猪的败血症和乳腺炎。然而，它是最广为人知的医院获得性感染的主要原因，并且是手术后伤口感染的常见原因。这种情况由于某些S.金黄色葡萄球菌对许多抗生素具有抗性（例如耐甲氧西林金黄色葡萄球菌），使其成为严重且难以治疗的问题。死亡人数归因于S。金黄色葡萄球菌感染可与归因于获得性免疫缺陷综合征的感染相比。在分子水平上对S.如果我们要设计新的治疗方法来预防或治愈感染，金黄色葡萄球菌的生物学和发病机理是必不可少的。ESX-1转运系统驱动S.金黄色葡萄球菌，并且已知当该系统失活时，S.金黄色葡萄球菌显示其引起感染的能力显著降低。我们寻求这种独特的细菌分泌机器的结构和功能的知识，并鉴定其货物。ESX-1系统由5-8种不同的蛋白质组分组成。我们将研究这些蛋白质如何相互作用以组装分泌机器，以及机器如何工作的分子基础。为了实现这一目标，我们必须推导出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动力的产生。我们已经取得了重大进展，其中六个蛋白质克隆，表达和纯化，两个结晶。我们将利用单晶X射线衍射方法来获得精确的分子结构，并利用一系列生物物理技术来研究蛋白质-蛋白质相互作用。了解蛋白质组分的结构以及它们如何相互作用是很重要的，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相互作用或阻止动力被用于分泌蛋白质，建立和延长感染。关于分泌的蛋白质和在细菌表面发现的结构的信息也可以为疫苗设计提供机会。

项目成果

The type VII secretion system of Staphylococcus aureus secretes a nuclease toxin that targets competitor bacteria.

• DOI: 10.1038/nmicrobiol.2016.183
• 发表时间: 2016-10-10
• 期刊: Nature microbiology
• 影响因子: 28.3
• 作者: Cao Z;Casabona MG;Kneuper H;Chalmers JD;Palmer T
• 通讯作者: Palmer T

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

• DOI: 10.1111/mmi.12707
• 发表时间: 2014-09
• 期刊: Molecular microbiology
• 影响因子: 3.6
• 作者: Kneuper H;Cao ZP;Twomey KB;Zoltner M;Jäger F;Cargill JS;Chalmers J;van der Kooi-Pol MM;van Dijl JM;Ryan RP;Hunter WN;Palmer T
• 通讯作者: Palmer T

Functional analysis of the EsaB component of the Staphylococcus aureus Type VII secretion system.

• DOI: 10.1099/mic.0.000580
• 发表时间: 2017-12
• 期刊: Microbiology (Reading, England)
• 作者: Casabona MG;Buchanan G;Zoltner M;Harkins CP;Holden MTG;Palmer T
• 通讯作者: Palmer T

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

ESSC是金黄色葡萄球菌型VII分泌的特异性决定因素。

• DOI: 10.1099/mic.0.000650
• 发表时间: 2018-05
• 期刊: Microbiology (Reading, England)
• 作者: Jäger F;Kneuper H;Palmer T
• 通讯作者: Palmer T

Haem-iron plays a key role in the regulation of the Ess/type VII secretion system of Staphylococcus aureus RN6390.

• DOI: 10.1099/mic.0.000579
• 发表时间: 2017-12
• 期刊: Microbiology (Reading, England)
• 作者: Casabona MG;Kneuper H;Alferes de Lima D;Harkins CP;Zoltner M;Hjerde E;Holden MTG;Palmer T
• 通讯作者: Palmer T