Characterisation of the Ess protein secretion system of Staphylococcus aureus, a key virulence factor.

金黄色葡萄球菌 Ess 蛋白分泌系统（关键毒力因子）的表征。

• 批准号: MR/M011224/1
• 负责人: Tracy Palmer
• 金额: $ 76.02万
• 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: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FM011224%2F1
• 关键词: Characterisation; Ess; protein; 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 Ess system - seeking to understand a central aspect of microbiology, namely how protein secretion machines work. This system has been shown to be essential for the virulence of Staphylococcus aureus.S. aureus is a commensal Gram positive bacterium responsible for a number of illnesses in humans ranging from minor skin infections, such as pimples and abscesses, Toxic shock syndrome, through to septicaemia and pneumonia. 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; MRSA), making it a severe and difficult to treat problem. 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.Our preliminary work and results from others has suggested that the Ess transport system drives the secretion of at least five 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 to determine the function of one of the secreted proteins.In order to secrete proteins, the machine needs to be energised. It is very likely that the EssC protein is responsible for providing the energy for this process, by breaking down an energy-rich compound in the cell called ATP. We want to understand the molecular basis for how the machine works. We have significant progress towards this by purifying and crystallising a large part of the EssC protein. We now wish to exploit single crystal X-ray diffraction methods to derive an accurate molecular structure for EssC. We want to build on this by understanding how EssC binds and hydrolyses ATP, and which other proteins in the Ess machine it interacts with.We want to confirm our preliminary results to determine which proteins are secreted by this machine. We would like to determine molecular structures for one of these proteins to understand how they work. Finally we want to understand how these proteins are secreted by the machinery in particular to see if they interact with EssC during their export.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产生毒素而致病的，这些毒素会分泌到宿主体内。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，可以控制这些毒素进入体外。我们正在研究其中一种机器——最近发现的Ess系统——试图理解微生物学的一个核心方面，即蛋白质分泌机器是如何工作的。该系统已被证明对金黄色葡萄球菌的毒力至关重要。金黄色葡萄球菌是一种共生革兰氏阳性细菌，可导致人类多种疾病，从轻微皮肤感染（如丘疹和脓肿）、中毒性休克综合征到败血症和肺炎。最广为人知的是它是医院获得性感染的主要原因，也是术后伤口感染的常见原因。一些金黄色葡萄球菌菌株对许多抗生素具有耐药性（例如耐甲氧西林金黄色葡萄球菌；MRSA），使这种情况更加恶化，使其成为一个严重且难以治疗的问题。如果我们要设计新的治疗方法来预防或治愈感染，在分子水平上理解金黄色葡萄球菌的生物学和发病机制是必不可少的。我们的初步工作和其他人的结果表明，Ess转运系统驱动金黄色葡萄球菌至少五种不同蛋白质的分泌，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。我们寻求这种独特的细菌分泌机器的结构和功能的知识，并确定其中一种分泌蛋白质的功能。为了分泌蛋白质，机器需要通电。很有可能是EssC蛋白通过分解细胞中一种叫做ATP的富含能量的化合物，为这一过程提供能量。我们想要了解机器如何工作的分子基础。通过纯化和结晶大部分EssC蛋白，我们在这方面取得了重大进展。我们现在希望利用单晶x射线衍射方法推导出EssC的精确分子结构。我们希望以此为基础，了解EssC如何结合和水解ATP，以及它与Ess机器中的哪些其他蛋白质相互作用。我们想确认我们的初步结果，以确定哪些蛋白质是由这台机器分泌的。我们想要确定其中一种蛋白质的分子结构，以了解它们是如何工作的。最后，我们想了解这些蛋白质是如何由机器分泌的，特别是看看它们在输出过程中是否与EssC相互作用。了解蛋白质成分的结构以及它们之间的相互作用是很重要的，因为从长远来看，这可能为直接设计或发现化合物的研究奠定基础，这些化合物可以阻止这些蛋白质相互作用，或者阻止原动力被用来分泌出建立和延长感染的蛋白质。有关分泌的蛋白质和在细菌表面发现的结构的信息也可能为疫苗设计提供机会。

项目成果

Heme-iron plays a key role in the regulation of the Ess/Type VII secretion system of Staphylococcus aureus RN6390

血红素铁在金黄色葡萄球菌 RN6390 Ess/VII 型分泌系统的调节中发挥关键作用

• DOI: 10.1101/145433
• 发表时间: 2017
• 作者: Casabona M

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

Membrane interactions and self-association of components of the Ess/Type VII secretion system of Staphylococcus aureus.

• DOI: 10.1002/1873-3468.12065
• 发表时间: 2016-02
• 期刊: FEBS letters
• 影响因子: 3.5
• 作者: Jäger F;Zoltner M;Kneuper H;Hunter WN;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