Crooke Anne Marie, Chand Anika K, Cui Zheng, Balskus Emily P
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA.
bioRxiv. 2024 Apr 18:2024.01.24.577118. doi: 10.1101/2024.01.24.577118.
Reactive functional groups, such as -nitrosamines, impart unique bioactivities to the natural products in which they are found. Recent work has illuminated enzymatic -nitrosation reactions in microbial natural product biosynthesis, motivating an interest in discovering additional metabolites constructed using such reactivity. Here, we use a genome mining approach to identify over 400 cryptic biosynthetic gene clusters (BGCs) encoding homologs of the -nitrosating biosynthetic enzyme SznF, including the BGC for chalkophomycin, a Cu-binding metabolite that contains a -type diazeniumdiolate and -hydroxypyrrole. Characterizing chalkophomycin biosynthetic enzymes reveals previously unknown enzymes responsible for -hydroxypyrrole biosynthesis, including the first prolyl--hydroxylase, and a key step in assembly of the diazeniumdiolate-containing amino acid graminine. Discovery of this pathway enriches our understanding of the biosynthetic logic employed in constructing unusual heteroatom-heteroatom bond-containing functional groups, enabling future efforts in natural product discovery and biocatalysis.
反应性官能团，如亚硝胺，赋予含有它们的天然产物独特的生物活性。最近的研究揭示了微生物天然产物生物合成中的酶促亚硝化反应，激发了人们对发现利用这种反应性构建的其他代谢产物的兴趣。在这里，我们使用基因组挖掘方法来鉴定400多个编码亚硝化生物合成酶SznF同源物的隐蔽生物合成基因簇（BGC），包括白垩霉素的BGC，白垩霉素是一种结合铜的代谢产物，含有一种δ型二氮烯二醇盐和δ-羟基吡咯。对白垩霉素生物合成酶的表征揭示了以前未知的负责δ-羟基吡咯生物合成的酶，包括首个脯氨酰-δ-羟化酶，以及含二氮烯二醇盐的氨基酸禾草碱组装中的关键步骤。该途径的发现丰富了我们对构建含不寻常杂原子-杂原子键官能团所采用的生物合成逻辑的理解，为未来天然产物发现和生物催化的研究奠定了基础。
