Molecular grammar of SurA-client interactions in the periplasm of gram-negative bacteria

革兰氏阴性菌周质中 SurA-客户相互作用的分子语法

• 批准号: BB/Y00034X/1
• 负责人: Antonio Calabrese
• 金额: $ 90.45万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FY00034X%2F1
• 关键词: Molecular; grammar; SurA; client; interactions

Antibiotic resistance is projected to cause 10 million deaths per year by 2050, with gram-negative pathogens comprising 9 of the 12 bacteria that pose the greatest threat to human health, according to the World Health Organisation. These gram-negative pathogens have a unique outer membrane (OM) that acts as a first line of defence against an assault from potentially harmful molecules to the bacteria, such as antibiotics. As a result, the OM is essential for bacterial survival and is one reason why certain bacteria are resistant to different types of antibiotics. Finding ways to prevent correct assembly of the OM may therefore produce new routes to kill gram-negative bacteria, or make them more susceptible to existing antibiotics. However, the mechanism by with the OM is built remains mysterious, making its assembly difficult to target with therapeutics.Here we propose to determine how key proteins of the OM - so-called outer membrane proteins (or OMPs) - are folded into the OM to create the usually impenetrable cell wall. OMPs play essential roles in bacterial virulence and survival, so by understanding how OMPs are assembled into the OM it may be possible to develop new drugs that target this essential process. A key protein involved in ensuring OMPs reach the OM is a chaperone protein called SurA. SurA is an attractive target for the development of new drugs to control gram-negative pathogens because perturbing the chaperone function of SurA results in a loss of bacterial viability and virulence along with increased sensitivity to antibiotics. However, in order to target the chaperone function of SurA, further work is needed to understand its mechanism of action. We have recently discovered that two key sites on SurA are responsible for recognising OMPs. This is exciting, as it suggests that one or both of these sites could make good targets for new drug-like molecules. However, we still do not understand how each of these two binding sites contribute to OMP binding and chaperone function. Here we propose to use information from an array of complementary and cutting-edge experimental methodologies (including NMR spectroscopy, mass spectrometry, single molecular Forster resonance energy transfer, biochemistry/biophysics and bioinformatics) to understand how each of the newly discovered OMP binding sites on SurA recognises specific signals within its OMP clients. Further, we propose to determine how these two binding sites work together to bring about its chaperone function, in particular regarding SurA's role in protecting newly synthesised OMPs from aggregation and facilitating their delivery to the OM. This will uncover the molecular features of SurA that are essential for assisting in OMP biogenesis, which, in the future, could lead to new strategies to develop much-needed antibiotics that target gram-negative pathogens that threaten humans, plants and animals.

据世界卫生组织称，到 2050 年，抗生素耐药性预计每年将导致 1000 万人死亡，其中对人类健康构成最大威胁的 12 种细菌中，有 9 种是革兰氏阴性病原体。这些革兰氏阴性病原体具有独特的外膜（OM），可作为抵御抗生素等潜在有害分子对细菌攻击的第一道防线。因此，OM 对于细菌的生存至关重要，也是某些细菌对不同类型抗生素产生耐药性的原因之一。因此，找到阻止 OM 正确组装的方法可能会产生杀死革兰氏阴性细菌的新途径，或者使它们对现有抗生素更敏感。然而，OM 的构建机制仍然神秘，使其组装难以通过治疗来靶向。在此，我们建议确定 OM 的关键蛋白（即所谓的外膜蛋白（或 OMP））如何折叠到 OM 中创建通常无法穿透的细胞壁。 OMP 在细菌毒力和生存中发挥着重要作用，因此通过了解 OMP 如何组装到 OM 中，有可能开发出针对这一重要过程的新药物。确保 OMP 到达 OM 的关键蛋白是一种称为 SurA 的伴侣蛋白。 SurA 是开发控制革兰氏阴性病原体的新药的一个有吸引力的靶标，因为扰乱 SurA 的伴侣功能会导致细菌活力和毒力丧失，同时对抗生素的敏感性增加。然而，为了靶向 SurA 的伴侣功能，需要进一步的工作来了解其作用机制。我们最近发现 SurA 上的两个关键站点负责识别 OMP。这是令人兴奋的，因为它表明这些位点中的一个或两个可以成为新的药物样分子的良好靶标。然而，我们仍然不明白这两个结合位点如何促进 OMP 结合和伴侣功能。在这里，我们建议使用一系列互补和前沿实验方法（包括核磁共振波谱法、质谱法、单分子福斯特共振能量转移、生物化学/生物物理学和生物信息学）的信息来了解每个新发现的 OMP 结合位点如何SurA 识别其 OMP 客户端内的特定信号。此外，我们建议确定这两个结合位点如何协同工作以实现其伴侣功能，特别是 SurA 在保护新合成的 OMP 免于聚集和促进其递送至 OM 方面的作用。这将揭示 SurA 的分子特征，这些特征对于协助 OMP 生物发生至关重要，这在未来可能会导致开发急需的抗生素的新策略，这些抗生素针对威胁人类、植物和动物的革兰氏阴性病原体。