Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States.
Department of Molecular Biology , Princeton University , Princeton , New Jersey 08544 , United States.
ACS Chem Biol. 2019 Apr 19;14(4):767-774. doi: 10.1021/acschembio.9b00049. Epub 2019 Mar 19.
Bacteria harbor an immense reservoir of potentially new and therapeutic small molecules in the form of "silent" biosynthetic gene clusters (BGCs). These BGCs can be identified bioinformatically but are sparingly expressed under normal laboratory growth conditions, or not at all, and therefore do not produce significant levels of the corresponding small molecule product. Several methods have been developed for activating silent BGCs. A major limitation for nearly all methods is that they require genetic procedures and/or do not report on the bioactivity of the cryptic metabolite. We herein report "Bioactivty-HiTES", an approach that links the bioactivity of cryptic metabolites to their induction while at the same time obviating the need for genetic manipulations. Using this method, we detected induction of cryptic antibiotics in three actinomycete strains that were tested. Follow-up studies in one case allowed us to structurally elucidate two cryptic metabolites, elicited by the β-blocker atenolol in Streptomyces hiroshimensis, with selective growth-inhibitory activity against Gram-negative bacteria, notably Escherichia coli and Acinetobacter baumannii. Atenolol turned out to be a global elicitor of secondary metabolism, and characterization of additional cryptic metabolites led to the discovery of a novel naphthoquinone epoxide. Bioactivity-HiTES is a general, widely applicable procedure that will be useful in identifying cryptic bioactive metabolites in the future.
细菌在“沉默”的生物合成基因簇 (BGCs) 中蕴藏着大量具有潜在新用途和治疗作用的小分子。这些 BGCs 可以通过生物信息学进行鉴定，但在正常实验室生长条件下很少表达，或者根本不表达，因此不会产生相应小分子产物的显著水平。已经开发了几种激活沉默 BGCs 的方法。几乎所有方法的一个主要限制是它们需要遗传操作，或者不报告隐匿代谢物的生物活性。我们在此报告“生物活性 HiTES”，这是一种将隐匿代谢物的生物活性与其诱导联系起来的方法，同时避免了遗传操作的需要。使用这种方法，我们检测到三种放线菌菌株中隐匿抗生素的诱导。在一个案例的后续研究中，我们能够对由β受体阻滞剂阿替洛尔在链霉菌中诱导产生的两种具有选择性抑菌活性的隐匿代谢物进行结构解析，对革兰氏阴性菌，特别是大肠杆菌和鲍曼不动杆菌有抑制作用。阿替洛尔原来是一种普遍的次级代谢诱导物，对其他隐匿代谢物的特征描述导致了一种新型萘醌环氧化物的发现。生物活性 HiTES 是一种通用的、广泛适用的程序，将来在鉴定隐匿生物活性代谢物方面将非常有用。
