Data_Sheet_1_Biosynthesis of coelulatin for the methylation of anthraquinone featuring HemN-like radical S-adenosyl-L-methionine enzyme.pdf

Bacterial aromatic polyketides are usually biosynthesized by the type II polyketide synthase (PKS-II) system. Advances in deoxyribonucleic acid (DNA) sequencing, informatics, and biotechnologies have broadened opportunities for the discovery of aromatic polyketides. Meanwhile, metagenomics is a biotechnology that has been considered as a promising approach for the discovery of novel natural products from uncultured bacteria. Here, we cloned a type II polyketide biosynthetic gene cluster (BGC) from the soil metagenome, and the heterologous expression of this gene cluster in Streptomyces coelicolor M1146 resulted in the production of three anthraquinones, two of which (coelulatins 2 and 3) had special hydroxymethyl and methyloxymethyl modifications at C2 of the polyketide scaffold. Gene deletion and in vitro biochemical characterization indicated that the HemN-like radical S-adenosyl-L-methionine (SAM) enzyme CoeI exhibits methylation and is involved in C2 modification.

细菌芳香族聚酮类化合物通常由II型聚酮合酶（type II polyketide synthase, PKS-II）系统生物合成。随着脱氧核糖核酸（deoxyribonucleic acid, DNA）测序技术、信息学及生物技术的发展，芳香族聚酮类化合物的发现机遇大幅拓展。与此同时，宏基因组学作为一项生物技术，被认为是从未培养细菌中发现新型天然产物的极具前景的方法。本研究从土壤宏基因组中克隆得到一个II型聚酮生物合成基因簇（biosynthetic gene cluster, BGC），将该基因簇在天蓝色链霉菌M1146（Streptomyces coelicolor M1146）中进行异源表达，最终获得三种蒽醌类化合物；其中两种（coelulatins 2和3）在聚酮骨架的C2位带有特殊的羟甲基和甲氧甲基修饰。基因敲除与体外生化表征实验表明，类HemN自由基S-腺苷-L-甲硫氨酸（S-adenosyl-L-methionine, SAM）酶CoeI具有甲基化活性，并参与C2位修饰过程。