Directed Evolution of a Non-Heme Iron Enzyme for Enantioselective Dearomative Nitrene Transfer: Synthesis of 3a-Aminopyrroloindoline Alkaloids
4 affiliations
- 1Department of Chemistry, BioScience Research Collaborative
- 2Rice University
- 3Centre for Artificial Intelligence Driven Drug Discovery, Faculty of Applied Sciences
- 4Polytechnic University
Abstract
Enzymatic nitrene-induced dearomatization represents an unexplored area of biocatalytic reactivity. Here, we report the directed evolution of AsqJ, a non-heme iron enzyme from aspoquinolone biosynthesis, to catalyze the first biocatalytic asymmetric dearomative nitrene transfer into indoles to furnish enantioenriched 3a-aminopyrroloindolines — a privileged scaffold in bioactive indole alkaloid natural products. Obtained through iterative semi-rational engineering and structure-informed mutagenesis, the final variant achieves up to 98% yield and >99% ee. The reaction accommodates a range of indole substrates, affording up to 86% isolated yield on preparative scale with consistently high enantioselectivity. Molecular dynamics simulations suggest that directed evolution established a new substrate-binding conformation that is distinct from the starting variant through a reorganized hydrogen-bonding network within a more preorganized active site. The synthetic utility of this platform is demonstrated through the total syntheses of two natural products, (+)-psychotriasine and (+)-psychotrimine. This work establishes asymmetric dearomative nitrene transfer as a new biocatalytic modality, extends the catalytic repertoire of non-heme iron enzymes to encompass asymmetric dearomatization, and provides a foundation for applying new-to-nature biocatalytic reactions in complex natural product synthesis.
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BibTeX
@misc{mu2026directed,
title = {{Directed Evolution of a Non-Heme Iron Enzyme for Enantioselective Dearomative Nitrene Transfer: Synthesis of 3a-Aminopyrroloindoline Alkaloids}},
author = {Xinpeng Mu and Ruiying Jiang and Jiali Xie and Shu Li and Hans Renata},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008359/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008359/v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Directed Evolution of a Non-Heme Iron Enzyme for Enantioselective Dearomative Nitrene Transfer: Synthesis of 3a-Aminopyrroloindoline Alkaloids
AU - Xinpeng Mu
AU - Ruiying Jiang
AU - Jiali Xie
AU - Shu Li
AU - Hans Renata
PY - 2026
DA - 2026/09/06
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008359/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008359/v1
AB - Enzymatic nitrene-induced dearomatization represents an unexplored area of biocatalytic reactivity. Here, we report the directed evolution of AsqJ, a non-heme iron enzyme from aspoquinolone biosynthesis, to catalyze the first biocatalytic asymmetric dearomative nitrene transfer into indoles to furnish enantioenriched 3a-aminopyrroloindolines — a privileged scaffold in bioactive indole alkaloid natural products. Obtained through iterative semi-rational engineering and structure-informed mutagenesis, the final variant achieves up to 98% yield and >99% ee. The reaction accommodates a range of indole substrates, affording up to 86% isolated yield on preparative scale with consistently high enantioselectivity. Molecular dynamics simulations suggest that directed evolution established a new substrate-binding conformation that is distinct from the starting variant through a reorganized hydrogen-bonding network within a more preorganized active site. The synthetic utility of this platform is demonstrated through the total syntheses of two natural products, (+)-psychotriasine and (+)-psychotrimine. This work establishes asymmetric dearomative nitrene transfer as a new biocatalytic modality, extends the catalytic repertoire of non-heme iron enzymes to encompass asymmetric dearomatization, and provides a foundation for applying new-to-nature biocatalytic reactions in complex natural product synthesis.
ER -