Lack of new antibiotics and increasing antimicrobial resistance are among the main concerns of healthcare communities nowadays, and these concerns necessitate the search for novel antibacterial agents. Recently, we discovered the cystobactamids—a novel natural class of antibiotics with broad‐spectrum antibacterial activity. In this work, we describe 1) a concise total synthesis of cystobactamid 507, 2) the identification of the bioactive conformation using noncovalently bonded rigid analogues, and 3) the first structure–activity relationship (SAR) study for cystobactamid 507 leading to new analogues with high metabolic stability, superior topoisomerase IIA inhibition, antibacterial activity and, importantly, stability toward the resistant factor AlbD. Deeper insight into the mode of action revealed that the cystobactamids employ DNA minor‐groove binding as part of the drug–target interaction without showing significant intercalation. By designing a new analogue of cystobactamid 919‐2, we finally demonstrated that these findings could be further exploited to obtain more potent hexapeptides against Gram‐negative bacteria.

中文翻译：

---

Cystobactamid 507：简洁的合成方法，作用方式和针对更强效抗生素的优化。

缺乏新的抗生素和增加的抗药性是当今医疗保健界的主要关注点，而这些关注点需要寻找新型的抗菌剂。最近，我们发现了半胱氨酸酰胺酶-一种具有广谱抗菌活性的新型天然抗生素。在这项工作中，我们描述了1）简洁的cystobactamid 507的全合成，2）使用非共价键合的刚性类似物鉴定生物活性构象，和3）首次针对cystobactamid 507产生新类似物的结构-活性关系（SAR）研究具有高的代谢稳定性，优异的拓扑异构酶IIA抑制，抗菌活性以及重要的是对耐药因子AlbD的稳定性。对作用方式的更深入了解表明，囊胞内酰胺利用DNA小沟结合作为药物与靶标相互作用的一部分，而没有表现出明显的嵌入。通过设计一种新的胱抑菌素919-2类似物，我们最终证明可以进一步利用这些发现来获得更有效的针对革兰氏阴性细菌的六肽。