Abstract：
Pyrroindomycins (PYRs) represent the only spirotetramate natural products discovered in nature, and possess potent activities against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Their unique structure and impressive biological activities make them attractive targets for synthesis and biosynthesis; however, the discovery and generation of new PYRs remains challenging. To date, only the initial components A and B have been reported. Herein, we report a mutasynthesis approach for the generation of nine new PYRs with varying acyl modifications on their deoxy-trisaccharide moieties. This was achieved by blocking the formation of the acyl group 1,8-dihydropyrrolo[2,3-b]indole (DHPI) via gene pyrK1 inactivation and supplying chemical acyl precursors. The gene pyrK1 encodes a DUF1864 family protein that probably catalyzes the oxidative transformation of L-tryptophan to DHPI, and its deletion results in the abolishment of DHPI-containing PYRs and the accumulation of three new PYRs either without acyl modification or with DHPI replaced by benzoic acid and pyrrole-2-carboxylic acid. Capitalizing on the capacity of the ΔpyrK1 mutant to produce new PYRs, we have successfully developed a mutasynthesis strategy for the generation of six novel PYR analogs with various aromatic acid modifications on their deoxy-trisaccharide moieties, showcasing the potential for generating structurally diverse PYRs. Overall, this research contributes significantly to understanding the biosynthesis of PYRs and offers valuable perspectives on their structural diversity.
摘要：
Pyrroindomycins（PYRs）代表了自然界中发现的唯一的螺四甲酸天然产物，并具有对耐甲氧西林金黄色葡萄球菌和耐万古霉素屎肠球菌的有效活性。它们独特的结构和令人印象深刻的生物活性使它们成为合成和生物合成的有吸引力的目标；然而，新PYR的发现和生成仍然具有挑战性。迄今为止,仅报告了初始组分A和B。在这里，我们报告了一种突变方法，用于生成9个新的PYR，其脱氧三糖部分具有不同的酰基修饰。这是通过基因pyrK1失活阻断酰基1,8-二氢吡咯并[2,3-b]吲哚（DHPI）的形成并提供化学酰基前体来实现的。基因pyrK1编码DUF1864家族蛋白，该蛋白可能催化L-色氨酸氧化转化为DHPI，及其缺失导致含DHPI的PYR的废除，并积累了三个新的PYR，无论是没有酰基修饰还是DHPI被苯甲酸和吡咯-2-羧酸取代。利用ΔpyrK1突变体产生新PYR的能力，我们已经成功开发了一种突变策略，用于生成六种新型PYR类似物，其脱氧-三糖部分具有各种芳香酸修饰，展示了产生结构多样化PYR的潜力。总的来说,这项研究为理解PYRs的生物合成做出了重要贡献，并为其结构多样性提供了有价值的观点。
