# Elucidate Mechanisms of Quinolone Alkaloid Biosynthesis via Iron(II)/2-Oxoglutarate Dependent Enzymes: Diverse, but Controlled Reactivity

> **NIH NIH R01** · CARNEGIE-MELLON UNIVERSITY · 2021 · $83,740

## Abstract

Project Summary/Abstract
2-Oxoglutarate (2OG) dependent nonheme mononuclear iron (NHM-Fe) enzymes catalyze an exceedingly
broad scope of reactions that are involved in key chemical transformations of many important biological
pathways, such as gene regulation, epigenetics, and natural product biosynthesis. Although detailed
mechanistic understandings of the canonical hydroxylation reactivity found in 2OG/NHM-Fe enzymes have
been developed in recent years, it remains unknown how this hydroxylation paradigm can fully explain non-
hydroxylation reactivity in this family of enzymes, such as desaturation and epoxidation. Furthermore, given the
catalytic abilities of 2OG/NHM-Fe enzymes to construct pharmaceutically valuable molecular scaffolds,
exploiting these enzymes for biocatalysis applications represents an attractive but under developed area for
expanding natural product based compound libraries. In this proposal, we seek to provide critical
improvements on these under developed areas through the studies of AsqJ, a novel multifunctional 2OG/NHM-
Fe enzyme that is involved in Viridicatin-type quinolone alkaloid biosynthesis in Aspergillus nidulans. AsqJ
catalyzes a chemically interesting sequential desaturation/epoxidation reaction to construct Viridicatin core
structure, which represents a chemically unexplored strategy for Viridicatin synthesis. A multi-faceted
experimental method will be utilized to elucidate AsqJ reaction mechanisms, which consists of organic
synthesis, molecular cloning, biochemical assays, protein crystallography, pre-steady state kinetics, and
advanced spectroscopic techniques. This method will be further supplemented with molecular dynamic
simulations to generate molecular level understandings of the AsqJ catalysis. It is expected that the proposed
research will provide critical improvements to the mechanistic understandings of desaturation and epoxidation,
two chemically challenging but under explored reactions catalyzed by 2OG/NHM-Fe enzymes, and further
explore mechanism based bioengineering approach to access viridicatin-type scaffolds.

## Key facts

- **NIH application ID:** 10197596
- **Project number:** 3R01GM125924-03S1
- **Recipient organization:** CARNEGIE-MELLON UNIVERSITY
- **Principal Investigator:** Yisong Guo
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $83,740
- **Award type:** 3
- **Project period:** 2018-09-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10197596

## Citation

> US National Institutes of Health, RePORTER application 10197596, Elucidate Mechanisms of Quinolone Alkaloid Biosynthesis via Iron(II)/2-Oxoglutarate Dependent Enzymes: Diverse, but Controlled Reactivity (3R01GM125924-03S1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10197596. Licensed CC0.

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