Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan.
Nat Commun. 2022 Jan 10;13(1):95. doi: 10.1038/s41467-021-27636-3.
Non-heme iron and α-ketoglutarate-dependent (Fe/αKG) oxygenases catalyze various oxidative biotransformations. Due to their catalytic flexibility and high efficiency, Fe/αKG oxygenases have attracted keen attention for their application as biocatalysts. Here, we report the biochemical and structural characterizations of the unusually promiscuous and catalytically versatile Fe/αKG oxygenase SptF, involved in the biosynthesis of fungal meroterpenoid emervaridones. The in vitro analysis revealed that SptF catalyzes several continuous oxidation reactions, including hydroxylation, desaturation, epoxidation, and skeletal rearrangement. SptF exhibits extremely broad substrate specificity toward various meroterpenoids, and efficiently produced unique cyclopropane-ring-fused 5/3/5/5/6/6 and 5/3/6/6/6 scaffolds from terretonins. Moreover, SptF also hydroxylates steroids, including androsterone, testosterone, and progesterone, with different regiospecificities. Crystallographic and structure-based mutagenesis studies of SptF revealed the molecular basis of the enzyme reactions, and suggested that the malleability of the loop region contributes to the remarkable substrate promiscuity. SptF exhibits great potential as a promising biocatalyst for oxidation reactions.
非血红素铁和 α-酮戊二酸依赖性（Fe/αKG）加氧酶催化各种氧化生物转化。由于其催化的灵活性和高效率，Fe/αKG 加氧酶作为生物催化剂引起了人们的极大关注。在这里，我们报告了参与真菌倍半萜 emervaridones 生物合成的异常混杂和催化多功能性 Fe/αKG 加氧酶 SptF 的生化和结构特征。体外分析表明，SptF 催化几种连续的氧化反应，包括羟化、去饱和、环氧化和骨架重排。SptF 对各种倍半萜类化合物表现出极强的广谱底物特异性，并能有效地从 terretonins 中产生独特的环丙烷环融合的 5/3/5/5/6/6 和 5/3/6/6/6 支架。此外，SptF 还能对甾体化合物进行羟化，包括雄酮、睾酮和孕酮，具有不同的区域选择性。SptF 的晶体学和基于结构的突变研究揭示了酶反应的分子基础，并表明环区的可变性有助于显著的底物混杂性。SptF 作为氧化反应的有前途的生物催化剂具有巨大的潜力。
