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Updated: Jul 11, 2025

A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s
Published on: September 25, 2017
Direct aromatic nitration by bacterial P450 enzymes.
Manyun Chen1, Vanisa Petriti1, Amit Mondal1
1Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, FL, United States.
Researchers engineered a bacterial cytochrome P450 enzyme, TxtE, into a self-sufficient biocatalyst for aromatic nitration. This novel biocatalyst, TxtE fused with a reductase domain, shows broad substrate scope for synthesizing nitroaromatics efficiently and sustainably.
Area of Science:
- Biocatalysis and Enzyme Engineering
- Synthetic Chemistry
- Green Chemistry
Background:
- Industrial production of nitroaromatics faces challenges like poor selectivity, pollution, and safety concerns.
- Nature offers biocatalytic strategies for aromatic nitration, inspiring the development of greener alternatives.
- Bacterial cytochrome P450 TxtE, involved in thaxtomin biosynthesis, can regioselectively nitrate the indole ring of L-tryptophan.
Purpose of the Study:
- To engineer a self-sufficient biocatalyst for aromatic nitration by creating fusion proteins of TxtE and a reductase domain.
- To optimize the catalytic performance of the engineered biocatalyst through linker length variation.
- To evaluate the substrate scope of the developed biocatalyst for synthesizing diverse nitroaromatic compounds.
Main Methods:
- Construction of artificial self-sufficient P450 chimeras by fusing TxtE with the reductase domain of P450BM3 (BM3R).
- Systematic evaluation of catalytic performance with varying linker lengths between the fused domains.
- Biochemical characterization, determination of kinetic parameters, and screening of L-tryptophan analogs as substrates.
Main Results:
- An engineered chimera with a 14-amino-acid linker (TB14) exhibited optimal catalytic activity.
- The TB14 biocatalyst demonstrated a broad substrate scope, successfully nitrating various L-tryptophan analogs.
- The developed biocatalyst offers a green and efficient alternative for aromatic nitration.
Conclusions:
- Engineered P450 fusion proteins can serve as efficient biocatalysts for aromatic nitration.
- The developed TB14 chimera provides a promising platform for the sustainable synthesis of nitroaromatics.
- The presented protocols can guide the engineering of other P450 enzymes for biocatalytic applications.
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