School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States.
ACS Chem Biol. 2022 Jun 17;17(6):1577-1585. doi: 10.1021/acschembio.2c00251. Epub 2022 Jun 6.
Natural product-encoding biosynthetic gene clusters (BGCs) within microbial genomes far outnumber the known natural products; chemical products from such BGCs remain cryptic. These silent BGCs hold promise not only for the elaboration of new natural products but also for the discovery of useful biosynthetic enzymes. Here, we describe a genome mining strategy targeted toward the discovery of substrate promiscuous natural product biosynthetic enzymes. In the genome of the methanotrophic bacterium Sph1, we discover a transcriptionally silent natural product BGC that encoded numerous ribosomally synthesized and post-translationally modified peptide (RiPP) natural products. These cryptic RiPP natural products were accessed using heterologous expression of the substrate peptide and biosynthetic enzyme-encoded genes. In line with our genome mining strategy, the RiPP biosynthetic enzymes in this BGC were found to be substrate promiscuous, which allowed us to use them in a combinatorial fashion with a similarly substrate-tolerant cyanobactin biosynthetic enzyme to introduce head-to-tail macrocyclization in the proteusin family of RiPP natural products.
微生物基因组中天然产物编码的生物合成基因簇（BGCs）的数量远远超过已知的天然产物；此类 BGC 产生的化学产物仍然是隐藏的。这些沉默的 BGC 不仅有望产生新的天然产物，还有望发现有用的生物合成酶。在这里，我们描述了一种针对发现具有底物通用性的天然产物生物合成酶的基因组挖掘策略。在产甲烷菌 Sph1 的基因组中，我们发现了一个转录沉默的天然产物 BGC，它编码了许多核糖体合成和翻译后修饰的肽（RiPP）天然产物。这些隐藏的 RiPP 天然产物是通过异源表达底物肽和生物合成酶编码基因来获得的。与我们的基因组挖掘策略一致，这个 BGC 中的 RiPP 生物合成酶具有底物通用性，这使我们能够以组合的方式使用它们，与同样具有底物耐受性的 cyanobactin 生物合成酶一起，在 proteusin 家族的 RiPP 天然产物中引入头对头的大环化。
