Scholarlink

<p><i>α</i>-Ketoglutarate-dependent mononuclear non-haem iron (<i>α</i>KG-NHFe) enzymes are catalytically versatile, yet OkaE is unique for synthesizing azetidine rings via C–C bond formation. Here, we report the unexpected multifunctionality of OkaE, which catalyzes sequential oxidations. Isotopic labelling studies demonstrate that a second O₂ molecule participates in sequential epoxidation and ring cleavage, incorporating two oxygen atoms within a single catalytic cycle to form the previously unknown structure, neuokaramine IV. Crystal structures of the OkaE•Co<sup>II</sup>•<i>α</i>KG•okaramine A complex unveil a unique methionine–<i>π</i> interaction network that facilitates substrate binding. Mutational and crystallographic analyses suggest this network fine-tunes substrate orientation relative to the metallo-centre, activating distinct reaction pathways at the 3a-OH or C8a positions. QM/MM simulations indicate that dynamic rotation of the Fe<sup>IV</sup>=O species initiates the cycle, enabling reaction bifurcation. This study elucidates the structural and mechanistic basis of OkaE’s reactivity, highlighting its potential as a programmable biocatalyst for natural product diversification.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Structural and mechanistic insights into azetidine-associated αKG-NHFe enzyme OkaE with multifunctional catalysis

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年2月17日

查看全文
  • Xinye Wang,
  • Junjie Yu,
  • Tonghai Liu,
  • Xuan Zhang,
  • Mengxi Ju,
  • Zhekai Xie,
  • Nathchar Naowarojna,
  • Linlu Ping,
  • Yaohong Dong,
  • Biyu Gong,
  • Yongtao Xie,
  • Yao Nie,
  • Tom Hsiang,
  • Ruibo Wu,
  • Lixin Zhang,
  • Pinghua Liu,
  • Guoliang Zhu,
  • Wupeng Yan,
  • Xueting Liu

摘要

α-Ketoglutarate-dependent mononuclear non-haem iron (αKG-NHFe) enzymes are catalytically versatile, yet OkaE is unique for synthesizing azetidine rings via C–C bond formation. Here, we report the unexpected multifunctionality of OkaE, which catalyzes sequential oxidations. Isotopic labelling studies demonstrate that a second O₂ molecule participates in sequential epoxidation and ring cleavage, incorporating two oxygen atoms within a single catalytic cycle to form the previously unknown structure, neuokaramine IV. Crystal structures of the OkaE•CoII•αKG•okaramine A complex unveil a unique methionine–π interaction network that facilitates substrate binding. Mutational and crystallographic analyses suggest this network fine-tunes substrate orientation relative to the metallo-centre, activating distinct reaction pathways at the 3a-OH or C8a positions. QM/MM simulations indicate that dynamic rotation of the FeIV=O species initiates the cycle, enabling reaction bifurcation. This study elucidates the structural and mechanistic basis of OkaE’s reactivity, highlighting its potential as a programmable biocatalyst for natural product diversification.