Bacillus Subtilis Chaperone/protease Mechanisms In Metabolic Shutdown

在许多种类的细菌中都有一种叫做ClpCP的旋转粉碎机，它可以处理不再需要的蛋白质。它由两部分组成：ClpC，它是一个6元环，利用ATP水解产生的能量将蛋白质的三维形状解开成一条单链，看起来像电线上的珠子。然后将其输入到ClpP中，ClpP以一对堆叠的7元环的形式被切割成可重复使用的小部件。ClpCP机器通过接头蛋白在细胞内被招募到特定的工作中。其中一项工作是破坏许多对新陈代谢很重要的蛋白质，当细菌形成长寿命的耐寒孢子以在恶劣条件下生存时，孢子需要变得代谢不活跃。在这项研究中，我的小组将研究一种新发现的蛋白质，MicA，它在细菌孢子形成过程中充当ClpCP的适配器。孢子形成是“医院超级细菌”持续存在的部分原因，因为孢子是一种寿命很长的细菌形式，对清洁剂有抵抗力，在天然肠道菌群不足的患者体内繁殖旺盛。我们打算使用间接技术揭示云母与ClpCP和底物结合时的详细分子形状，因为它们太小，即使使用强大的显微镜也无法看到。我们专门测量蛋白质的形状，并通过人工大量生产蛋白质，在细菌的帮助下，它们成为我们的“蛋白质工厂”。然后，当我们将x射线或电子从蛋白质上反射或将它们置于强磁场中时，我们通过处理它们的行为来推断蛋白质的分子结构。每种技术都有其优点和缺点，但我们的组合方法可以产生互补的信息，填补仅使用其中一种方法留下的空白。我们将与微生物学家、电子显微镜学家和伴侣科学家合作，为彼此的实验提供信息，以建立细菌孢子形成这一重要步骤的机制图。例如，如果我们在我们的一种蛋白质中发现了一个突变，使其与同伴结合得更紧密，我们的合作者可以在细菌中进行同样的突变，以测试它是否在生命系统中具有预期的效果。通过解决这一难题，我们希望能够在设计新型抗生素方面处于更有利的地位，以解决日益严重的细菌耐药性问题，该项目还对了解健康和疾病许多方面的代谢和蛋白质质量控制具有更长远的意义。

In many types of bacteria there is a rotary-shredder machine called ClpCP that acts as waste disposal for proteins that are no longer needed. It is built of two parts: ClpC, which is a 6-membered ring that uses energy from ATP hydrolysis to unwind the three dimensional shapes of proteins into a single chain that looks like beads on a wire. This is then fed into ClpP, which takes the form of a stacked pair of 7-membered rings, to be chopped up into small reusable parts. The ClpCP machine is recruited to particular jobs within cells by adaptor proteins. One of these jobs is to destroy many proteins that are important for metabolism, when bacteria form long-lived hardy spores to survive harsh conditions as the spores need to become metabolically inactive. In this study my group will examine a newly discovered protein, MicA, which acts an adaptor to ClpCP during bacterial spore formation. Sporulation is partially responsible for the persistence of 'hospital superbugs' as spores are a long-lived bacterial form, resistant to cleaning agents and thriving in patients depleted of natural gut microflora.We intend to uncover the detailed molecular shapes of MicA when it is bound to ClpCP and substrates using indirect techniques as they are too small to see even using powerful microscopes. We specialise in measuring protein shapes and the way they fit together by producing them artificially in large quantities, with the help of bacteria which act as our 'protein factories'. We then deduce the proteins' molecular structures by processing their behaviour when we bounce X-rays or electrons off them or put them in strong magnetic fields. Each of these techniques has its strengths and weaknesses but our combined approach can yield complementary information filling in the gaps left by using just one of the methods. Collaborating with microbiologists, electron microscopists and chaperone scientists, we will feed information into each others' experiments to build up a mechanistic picture of this important step in bacterial spore formation. For example, if we identify a mutation in one of our proteins that makes it bind more tightly to its partner our collaborator can make the same mutation within bacteria to test whether it has the predicted effect in living systems.By solving this jigsaw puzzle we hope to be in a stronger position to design novel antibiotics to attack the increasing problem of bacterial drug resistance and the project also has longer term implications for understanding metabolism and protein quality control in many aspects of health and disease.