Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
College of Pharmacy, Chonnam National University, Gwangju, 61186, South Korea.
Angew Chem Int Ed Engl. 2022 Jan 21;61(4):e202114022. doi: 10.1002/anie.202114022. Epub 2021 Dec 10.
Microbial secondary metabolite discovery is often conducted in pure monocultures. In a natural setting, however, where metabolites are constantly exchanged, biosynthetic precursors are likely provided by symbionts or hosts. In the current work, we report eight novel and architecturally unusual secondary metabolites synthesized by the bacterial symbiont Phaeobacter inhibens from precursors that, in a native context, would be provided by their algal hosts. Three of these were produced at low titres and their structures were determined de novo using the emerging microcrystal electron diffraction method. Some of the new metabolites exhibited potent algaecidal activity suggesting that the bacterial symbiont can convert algal precursors, tryptophan and sinapic acid, into complex cytotoxins. Our results have important implications for the parasitic phase of algal-bacterial symbiotic interactions.
微生物次生代谢产物的发现通常是在纯培养物中进行的。然而，在自然环境中，代谢物不断交换，生物合成前体可能由共生体或宿主提供。在当前的工作中，我们报告了由细菌共生体 Phaeobacter inhibens 从其藻类宿主提供的前体中合成的八种新型和结构不寻常的次生代谢产物。其中三种以低浓度产生，其结构使用新兴的微晶电子衍射方法从头确定。一些新的代谢产物表现出强烈的杀藻活性，这表明细菌共生体可以将藻类前体色氨酸和芥子酸转化为复杂的细胞毒素。我们的研究结果对藻类-细菌共生相互作用的寄生阶段具有重要意义。
