Understanding DNA transport by topo IV and gyrase to counter antimicrobial resistance

了解拓扑 IV 和旋转酶的 DNA 转运以对抗抗菌药物耐药性

• 批准号: MR/T000848/1
• 负责人: Larry Mark Fisher
• 金额: $ 107.91万
• 依托单位: St George's, University of London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FT000848%2F1
• 关键词: Understanding; DNA; transport; topo; IV

Antibiotic resistance is a worldwide problem and a major challenge for the treatment of infection. Bacteria are becoming resistant to our most important antibiotics jeopardising even straightforward medical procedures. One serious threat is posed by Streptococcus pneumoniae, a global pathogen that causes life-threatening pneumonia and meningitis in childern and the elderly. Increasingly, S. pneumoniae isolates are found to be resistant to penicillins and to fluoroquinolones, which are key members of our antibiotic arsenal. It is known that fluoroquinolones interfere with DNA breakage by gyrase and topoisomerase (topo) IV, two enzymes that untangle DNA and are required for bacterial DNA replication and growth. Remarkably, these enzymes make a transient break in DNA and cross another DNA through the break. By this means, gyrase can remove twists when DNA is copied in the cell, and topo IV can unlink tangled chromosomes ahead of cell division. By using X-ray crystallography to solve the structure of these enzymes bound to DNA and fluoroquinolones, we now understand in detail how quinolones bind and trap the DNA break and how resistance arises. However, almost nothing is known about the nature of the transported DNA, how it is recognised, captured and then crossed through the DNA break. To fill this gap in knowledge, and guided by our recent structure of a topo IV-transport DNA complex, we shall use a combination of techniques including X-ray crystallography, cryo-electron microscopy, fluorescence and protein biochemistry to establish the mechanism of DNA transport by topo IV and gyrase from S. pneumoniae and from Klebsiella pneumoniae, another pathogen highly resistant to quinolones. Completion of the work will be a major contribution in understanding these fascinating molecular machines and will provide new opportunites for design of new drugs that overcome resistance by targeting DNA transport. New drugs will be essential in addressing the global emergency of antimicrobial resistance.

抗生素耐药性是一个世界性问题，也是感染治疗的重大挑战。细菌对我们最重要的抗生素产生了耐药性，甚至危及简单的医疗程序。肺炎链球菌构成了一个严重的威胁，它是一种全球病原体，可导致儿童和老年人危及生命的肺炎和脑膜炎。越来越多的肺炎链球菌分离株被发现对青霉素和氟喹诺酮类药物具有耐药性，而青霉素和氟喹诺酮类药物是我们抗生素库的关键成员。众所周知，氟喹诺酮类药物会干扰旋转酶和拓扑异构酶 (topo) IV 造成的 DNA 断裂，这两种酶可以解开 DNA，是细菌 DNA 复制和生长所必需的。值得注意的是，这些酶会在 DNA 中产生短暂的断裂，并通过断裂处与另一个 DNA 交叉。通过这种方式，当 DNA 在细胞中复制时，旋转酶可以消除扭曲，而拓扑 IV 可以在细胞分裂前断开缠结的染色体。通过使用 X 射线晶体学来解析这些与 DNA 和氟喹诺酮类药物结合的酶的结构，我们现在详细了解了喹诺酮类药物如何结合和捕获 DNA 断裂以及耐药性是如何产生的。然而，人们对所运输的 DNA 的性质、如何识别、捕获并穿过 DNA 断裂点几乎一无所知。为了填补这一知识空白，并以我们最近的拓扑 IV 转运 DNA 复合物结构为指导，我们将结合使用 X 射线晶体学、冷冻电子显微镜、荧光和蛋白质生物化学等技术，建立拓扑 IV 和肺炎链球菌和肺炎克雷伯菌（另一种高度耐药的病原体）的旋转酶进行 DNA 转运的机制。 喹诺酮类药物。这项工作的完成将为理解这些令人着迷的分子机器做出重大贡献，并将为设计通过靶向 DNA 转运来克服耐药性的新药物提供新的机会。新药对于解决全球抗菌药物耐药性的紧急情况至关重要。