Exploring the potential of caelestamide A, a novel antibiotic with activity against Enterobacter cloacae

1.27 2019年有100万人死亡直接归因于抗菌素耐药性。因此，迫切需要发现和开发能够克服对当前治疗的耐药性的新型抗生素。目前临床上使用的抗生素绝大多数是从细菌和真菌中分离的天然产物或半合成衍生物，Caelestamide A是最近被鉴定为Streptomyces caelestis中的一个隐蔽生物合成基因簇的产物的新型抗生素，其结构与salinamide A相关，salinamide A是一种RNA聚合酶抑制剂，具有对抗WHO“关键优先”病原体阴沟肠杆菌的有希望的活性。初步实验表明，西来酰胺A对阴沟肠杆菌也有活性，其与盐酰胺A的结构相关性表明其具有相似的作用机制。这是重要的，因为RNA聚合酶是一个经过充分验证但开发不足的靶标。本项目旨在进一步研究卡来甾胺A的抗菌活性，确认其靶向RNA聚合酶，并开发生产类似物的方法以阐明其结构-活性关系，本项目还旨在研究卡来甾胺产生菌S. caelestis，并确定是否有类似的自我耐药机制是由放线菌，产生一个结构上不相关的抗生素类的目标翻译。这些研究将建立一个通用的新机制，在产抗生素的细菌，可以利用发现新的抗生素在未来的自我抗性。学生将在学生期间接受以下培训：天然产物分离和结构解析;抗生素敏感性测试;生物合成工程;细菌分子遗传学;生物信息学;长读测序;蛋白质X射线晶体学和对接模拟。

1.27 million deaths were directly attributed to antimicrobial resistance in 2019. There is, therefore, an urgent need to discover and develop novel antibiotics that can overcome resistance to current treatments. The overwhelming majority of antibiotics in current clinical use are natural products isolated from bacteria and fungi, or semi-synthetic derivatives.Caelestamide A, a novel antibiotic recently identified as the product of a cryptic biosynthetic gene cluster in Streptomyces caelestis, is structurally related to salinamide A, an RNA polymerase inhibitor with promising activity against the WHO "critical priority" pathogen Enterobacter cloacae. Preliminary experiments have shown that caelestamide A is also active against Enterobacter cloacae and its structural relatedness to salinamide A suggests it has a similar mechanism of action. This is significant because RNA polymerase is a well validated but underexploited target. This project aims to further investigate the antibacterial activity of caelestamide A, confirm that it targets RNA polymerase and develop methods for producing analogues to illuminate its structure-activity relationship.This project also aims to investigate a proposed novel mechanism of self-resistance in the caelestamide producer, S. caelestis, and establish whether a similar self-resistance mechanism is employed by Actinobacteria that produce a structurally unrelated class of antibiotics that targets translation. These studies will establish a general new mechanism for self-resistance in antibiotic-producing bacteria that could be exploited to discover novel antibiotics in the future. The student will be trained in the following during the studentship: natural product isolation and structure elucidation; antibiotic susceptibility testing; biosynthetic engineering; bacterial molecular genetics; bioinformatics; long-read sequencing; protein X-ray crystallography and docking simulations.