Structure-based drug design against a biosecurity pathogen BB/M009122/1

伯纳蒂克希菌是q热的病原体，q热是一种全球流行的人畜共患疾病，特别是在英国西南部。伯氏梭菌是反刍动物的专性病原体：在牲畜中，它会导致流产和死产，造成明显的经济后果。伯纳蒂菌是人类的机会致病菌，感染剂量极低。q热会引起严重的流感样症状。虽然这些症状通常会自行消退，但有些患者需要住院治疗，其中一些患者会出现严重的并发症（例如心肌炎）。伯纳蒂杆菌是中东地区英国服役人员所患的所谓“沙漠热”的病原体之一，并与慢性疲劳综合征有关。显然需要有效的治疗伯氏梭菌。我们是一个正在进行的（BBSRC资助的）项目的一部分，该项目利用目前最好的候选疫苗伯氏杆菌的多糖o抗原生产疫苗。这种o型抗原含有两种极不寻常的糖（病毒糖和二氢羟基链球菌）。我们已经确定了几个生物合成蛋白，支持我们对生物合成的假设。这些酶显示出至少两种新的酶活性，这可能为制造特异性抑制剂提供了极好的机会。我们有大量制备蛋白质的方案，这应该足以确定蛋白质结构。主要主管将与Diamond Light Source合作，使用即将到来的微电子衍射方法作为该结构解决方案的一部分。在这个项目中，学生将从生物合成途径中选择科学上最有趣的蛋白质。学生将确定这些蛋白质的结构，并将测试野生型酶和选择的突变体的酶活性。学生将测试重组大肠杆菌途径中酶的活性，以确认突变体的影响。学生将特别寻找在全细胞环境中可能有价值的活性改变的酶变体。该学生还将使用建模软件使用分子动力学和量子力学模拟来研究酶，以支持提出的酶机制。然后，这些数据将用于模拟药物与蛋白质的结合，作为药物开发的第一步。学生的工作将展示在o抗原途径的新酶的机制。该学生的工作也将有助于疫苗开发和药物发现的第一阶段重组o抗原的发展。因此，这项工作将具有学术和实际的成果。

Coxiella burnetii is the causative agent of Q-fever, a zoonotic disease endemic globally and particularly in the South-West in the UK. C. burnetii is an obligate pathogen of ruminants: in livestock it causes abortions and still-births, with obvious economic consequences. C. burnetii is an opportunistic pathogen of humans with a very low infectious dose. Q-fever causes serious flu-like symptoms. Whilst these are usually self-resolving, some patients require hospital treatment, and some of these go on to suffer serious complications (e.g. myocarditis). C. burnetii is one of the causative agents of the so-called "desert fever" suffered by UK service personal in the Middle East, and has been associated with chronic fatigue syndrome. There is a clear need for effective treatments for C. burnetii. We are part of an ongoing (BBSRC funded) programme to produce a vaccine using the polysaccharide O-antigen of C. burnetii, the best current vaccine candidate. This O-antigen contains two highly unusual sugars (virenose and dihydrohydroxystreptose). We have identified several of the biosynthetic proteins that support our hypotheses on the biosynthesis. These enzymes display at least two novel enzyme activities, which may provide excellent opportunities to make specific inhibitors. We have protocols to prepare proteins in high quantities, which should be sufficient to determine the protein structures. The main supervisor will collaborate with Diamond Light Source to use the upcoming micro-electron diffraction method as part of this structure solution.In this project, the student will select the most scientifically interesting proteins from the biosynthetic pathway. The student will determine the structure of these proteins, and will test the wild-type enzyme and selected mutants for enzyme activity. The student will test the activity of the enzymes in recombinant E. coli pathways to confirm the effects of mutants. The student will particularly look for enzyme variants that display altered activity that might be valuable in the whole-cell context. The student will also work with modelling software to study the enzymes using molecular dynamics and quantum mechanical simulations to support proposed enzymatic mechanisms. These data will then be used to model drug binding to the proteins as a first step towards drug development.The student's work will demonstrate the mechanisms of the novel enzymes in the O-antigen pathway. The student's work will also contribute to the development of recombinant O-antigen for vaccine development and the first stages of drug discovery. This work will therefore have both academic and practical outputs.