Myxobacteria are a prolific source of structurally diverse natural products, and one of the best-studied myxobacterial products is the siderophore myxochelin. Herein, we report two new compounds, myxochelins N (1) and O (2), that are nicotinic paralogs of myxochelin A, from the terrestrial myxobacterium Archangium sp. SDU34; 2 is functionalized with a rare 2-oxazolidinone. A precursor-feeding experiment implied that the biosynthesis of 1 or 2 was due to altered substrate specificity of the loading module of MxcE, which likely accepts nicotinic acid and benzoic acid instead of more conventional 2,3-dihydroxybenzoic acid. We also employed a phylogenomic approach to map the evolutionary relationships of the myxochelin biosynthetic gene clusters (BGCs) in all the available myxobacterial genomes, to pave the way for the future discovery of potentially hidden myxochelin derivatives. Although the biological function of 1 and 2 is unclear yet, this work underpins that even extensively studied BGCs in myxobacteria can still produce new chemistry.

中文翻译：

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来自 Archangium sp. 的烟碱黏附素的发现和生物合成。SDU34

粘细菌是结构多样的天然产物的丰富来源，研究最多的粘细菌产品之一是铁载体粘螯素。在此，我们报告了两种新化合物，粘螯素 N ( 1 ) 和 O ( 2 )，它们是来自陆地粘细菌Archangium sp. 的粘螯素 A 的烟碱旁系同源物。SDU34; 2被一种罕见的 2-恶唑烷酮官能化。前体喂养实验表明1或2的生物合成是由于 MxcE 加载模块的底物特异性改变，它可能接受烟酸和苯甲酸，而不是更传统的 2,3-二羟基苯甲酸。我们还采用系统基因组学方法来绘制所有可用粘细菌基因组中粘螯素生物合成基因簇 (BGC) 的进化关系，为未来发现潜在隐藏的粘螯素衍生物铺平道路。尽管1和2的生物学功能尚不清楚，但这项工作表明，即使对粘细菌中的 BGC 进行了广泛研究，仍然可以产生新的化学物质。