Department of Chemistry, Duke University, Durham, North Carolina 27710, United States.
Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, United States.
Biochemistry. 2021 Jul 20;60(28):2231-2235. doi: 10.1021/acs.biochem.1c00327. Epub 2021 Jul 9.
Peptidyl nucleoside antifungals, represented by nikkomycins and polyoxins, consist of an unusual six-carbon nucleoside [aminohexuronic acid (AHA)] ligated to a nonproteinogenic amino acid via an amide bond. A recent study suggested that AHA is biosynthesized through cryptic phosphorylation, where a 2'-phosphate is introduced early in the pathway and required to form AHA. However, whether 2'-phosphorylation is necessary for the last step of biosynthesis, the formation of the amide bond between AHA and nonproteinogenic amino acids, remains ambiguous. Here, we address this question with comprehensive and characterizations of PolG and NikS, which together provide strong evidence that amide ligation proceeds with 2'-phosphorylated substrates in both pathways. Our results suggest that 2'-phosphorylation is retained for the entirety of both nikkomycin and polyoxin biosynthesis, providing important insights into how cryptic phosphorylation assists with nucleoside natural product biosynthesis.
肽核苷类抗真菌剂，以 nikkomycins 和 polyoxins 为代表，由一个不寻常的六碳核苷[氨基己糖酸（AHA）]通过酰胺键与非蛋白氨基酸连接而成。最近的一项研究表明，AHA 是通过隐蔽磷酸化生物合成的，其中在途径早期引入 2'-磷酸，并且需要形成 AHA。然而，2'-磷酸化是否对于 AHA 和非蛋白氨基酸之间的酰胺键形成的最后一步生物合成是必要的，仍然不清楚。在这里，我们通过全面和特征化的 PolG 和 NikS 来解决这个问题，这两者都提供了强有力的证据表明酰胺键连接在两条途径中都使用了 2'-磷酸化的底物。我们的结果表明，2'-磷酸化在 nikkomycin 和 polyoxin 生物合成的整个过程中都被保留下来，这为隐蔽磷酸化如何协助核苷天然产物生物合成提供了重要的见解。
