FTIR secondary structure assignments.

The overconsumption and inappropriate use of antibiotics is escalating antibiotic resistance development, which is now one of the 10 top threats to global health. Introducing antibiotics with a novel mode of action into clinical use is urgently needed to address this issue. Deliberately inducing aggregation of target proteins and disrupting protein homeostasis in bacteria via amyloidogenic peptides, also called Pept-ins (from peptide interferors), can be lethal to bacteria and shows considerable promise as a novel antibiotic strategy. However, the translation of Pept-ins into the clinic requires further investigation into their mechanism of action and improvement of their therapeutic window. Therefore, we performed systematic structure modifications of 2 previously discovered Pept-ins, resulting in 179 derivatives, and investigated the corresponding impact on antimicrobial potency, cellular accumulation, and ability to induce protein aggregation in bacteria, in vitro aggregation property, and toxicity on mammalian cells. Our results show that both Pept-in accumulation and aggregation of target proteins in bacteria are requisite for Pept-in mediated antimicrobial activity. Improvement of these two parameters can be achieved via increasing the number of arginine residues, increasing Pept-in aggregation propensity, optimizing the aggregate core structure, adopting β-turn linkers, or forming a disulphide bond. Correspondingly, improvement of these two parameters can enhance Pept-in antimicrobial efficacy against wildtype E. coli BL21 used in the laboratory as well as clinically isolated multidrug-resistant strain E. coli ATCC, A. baumannii, and K. pneumoniae.

抗生素过度使用与不合理应用正加剧抗生素耐药性的发展，而后者现已成为全球十大健康威胁之一。为应对这一公共卫生难题，亟需将作用机制全新的抗生素投入临床应用。通过淀粉样肽（amyloidogenic peptides）——又称Pept-ins（源自peptide interferors）——刻意诱导细菌靶蛋白聚集、破坏细菌蛋白质稳态，可对细菌产生致死效应，该策略作为新型抗菌手段展现出可观的应用前景。然而，将Pept-ins转化为临床用药，仍需进一步探究其作用机制并优化其治疗窗。为此，我们对2种此前已发现的Pept-ins开展系统性结构修饰，获得179种衍生物，并系统考察了其对细菌抗菌活性、细胞蓄积能力、诱导细菌蛋白聚集的能力、体外聚集特性以及对哺乳动物细胞毒性的相应影响。研究结果显示，Pept-ins的细胞蓄积能力与细菌内靶蛋白的聚集能力，均为Pept-ins介导抗菌活性的必要条件。通过增加精氨酸残基数目、提升Pept-ins的聚集倾向、优化聚集核心结构、采用β转角连接子（β-turn linkers）或形成二硫键，可改善上述两项参数。相应地，优化这两项参数可提升Pept-ins对实验室使用的野生型大肠杆菌（E. coli）BL21，以及临床分离的多重耐药菌株大肠杆菌（E. coli）ATCC、鲍曼不动杆菌（A. baumannii）与肺炎克雷伯菌（K. pneumoniae）的抗菌效力。