# Taming radical enzymes through directed evolution and structural analysis

> **NIH NIH F32** · MASSACHUSETTS INSTITUTE OF TECHNOLOGY · 2020 · $65,310

## Abstract

Project Summary
Glycyl radical enzymes (GREs) catalyze diverse chemical transformations critical to both human health and the
environment. The unifying characteristic of GREs–a stable glycyl radical cofactor–enables challenging,
otherwise inaccessible chemistry, but is extremely oxygen sensitive. Thus, this still expanding family of
enzymes is prevalent in anaerobic environments such as the human gut and marine seeps. GRE activity has
been implicated in liver, heart, and kidney diseases and could prove uniquely effective in bioremediation
efforts; however, most GREs remain uncharacterized. Additionally, the molecular detail of how the large
breadth of GRE-catalyzed chemistry is accomplished is not yet understood. The work described within this
proposal will further illuminate GRE mechanism as well as explore GRE use in biocatalysis. Specifically, this
work will explore a class of GREs termed X-succinate synthases (XSS). XSS enzymes catalyze the
hydroalkylation of fumarate, in which new C–C bonds are forged between fumarate and unactivated
hydrocarbon substrates. Through this mechanism, XSS-containing organisms are able to degrade hydrocarbon
pollutants in even the most recalcitrant regions for environmental remediation. Beyond bioremediation, XSS
enzymes enable remarkable chemistry and could serve as an important addition to our current C–H
functionalization toolkit. Here, I aim to understand XSS enzymes in molecular detail though structural biology
and develop novel methodologies that will allow for engineering of this enzyme class, as well as radical
enzymes more broadly. Collectively, this work will allow us further insight into the ways in which Nature uses
enzymes to achieve remarkable chemistry and will allow us to begin to harness the powerful radical chemistry
Nature has to offer.

## Key facts

- **NIH application ID:** 9848441
- **Project number:** 5F32GM129882-02
- **Recipient organization:** MASSACHUSETTS INSTITUTE OF TECHNOLOGY
- **Principal Investigator:** Mary Catherine Andorfer
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $65,310
- **Award type:** 5
- **Project period:** 2019-01-01 → 2021-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9848441

## Citation

> US National Institutes of Health, RePORTER application 9848441, Taming radical enzymes through directed evolution and structural analysis (5F32GM129882-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9848441. Licensed CC0.

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