David Braley Center for Antibiotic Discovery, M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
Nat Biotechnol. 2019 Oct;37(10):1149-1154. doi: 10.1038/s41587-019-0241-9. Epub 2019 Sep 9.
Actinobacteria, which are one of the largest bacterial phyla and comprise between 13 and 30% of the soil microbiota, are the main source of antibiotic classes in clinical use. During screens for antimicrobials, as many as 50% of actinomycete strains are discarded because they produce a known antibiotic (Supplementary Fig. 1) (ref. ). Despite each strain likely having the capacity to produce many compounds, strains are abandoned because the already characterized antibiotic could interfere with screening for, or purification of, newly discovered compounds. We applied CRISPR-Cas9 genome engineering to knockout genes encoding two of the most frequently rediscovered antibiotics, streptothricin or streptomycin, in 11 actinomycete strains. We report that this simple approach led to production of different antibiotics that were otherwise masked. We were able to rapidly discover rare and previously unknown variants of antibiotics including thiolactomycin, amicetin, phenanthroviridin and 5-chloro-3-formylindole. This strategy could be applied to existing strain collections to realize their biosynthetic potential.
放线菌是最大的细菌门之一，占土壤微生物群的 13%至 30%，是临床使用的抗生素类药物的主要来源。在筛选抗微生物药物的过程中，多达 50%的放线菌菌株被丢弃，因为它们产生已知的抗生素（补充图 1）（参考文献）。尽管每个菌株可能都有产生许多化合物的能力，但由于已经确定的抗生素可能会干扰新发现化合物的筛选或纯化，因此这些菌株被放弃。我们应用 CRISPR-Cas9 基因组工程技术，敲除了 11 株放线菌中编码两种最常被重新发现的抗生素——链霉素或链霉素的基因。我们报告说，这种简单的方法导致了原本被掩盖的不同抗生素的产生。我们能够快速发现罕见的、以前未知的抗生素变体，包括硫内酯霉素、阿米卡星、菲蒽酮和 5-氯-3-甲酰吲哚。这种策略可以应用于现有的菌株库，以实现其生物合成潜力。
