# Mechanism of carbon skeleton formation in molybdenum cofactor biosynthesis

> **NIH NIH R01** · DUKE UNIVERSITY · 2020 · $457,803

## Abstract

Project Summary/Abstract
Molybdenum cofactor (Moco) is a redox cofactor found in almost all organisms. In humans, it is essential for
normal brain development, and mutations in Moco biosynthetic genes cause the fatal and currently incurable
disease, Moco deficiency (MoCD). In pathogenic bacteria, Moco is essential for their growth under hypoxic and
nutrient limiting environments, and therefore essential for pathogen persistence in mammalian hosts. Chronic
bacterial infections are resistant to many antibiotics and cause the recurrence of acute symptoms. However, the
development of therapeutics against MoCD or antibiotics targeting Moco biosynthesis in pathogenic bacteria are
currently difficult due to our limited understanding of the mechanism of Moco biosynthesis. The long-term goal
of this project is to provide a mechanistic understanding of Moco biosynthesis in pathogenic bacteria as well as
in humans. The focus of the current application is the mechanism of two enzymes (MoaA and MoaC) responsible
for the formation of the pyranopterin structure of Moco from guanine 5'-triphosphate (GTP). While the catalytic
functions of MoaA and MoaC had remained ambiguous for >20 years, we recently demonstrated that MoaA
catalyzes the transformation of GTP into 3',8-cyclo-dihydro-GTP (3',8-cH2GTP), while MoaC catalyzes the
conversion of 3',8-cH2GTP to cPMP. In this application, we will investigate the catalytic mechanisms of MoaA
and MoaC in both humans and bacteria through the following three Aims. In Aim 1, the redox function of 4Fe-4S
clusters in MoaA will be investigated both in the resting state and during turnover to address one of the key
unsolved mysteries of the radical SAM enzyme mechanisms. In Aim 2, the function of the C-terminal tail of MoaA
and the mechanism of peptide rescue of MoCD-causing mutations will be investigated through NMR, X-ray
crystallography and biochemical assays using bacterial and human enzymes. In Aim 3, we will test a covalent
and non-covalent mechanisms for MoaC catalysis and investigate the generality of mechanism-based inhibition
of bacterial and human enzymes. The proposed research is significant because it will provide mechanistic
insights into the formation of the Moco backbone and the scientific basis for future development of Moco
biosynthesis inhibitors and novel therapeutics to treat MoCD.

## Key facts

- **NIH application ID:** 10058693
- **Project number:** 2R01GM112838-05
- **Recipient organization:** DUKE UNIVERSITY
- **Principal Investigator:** Kenichi Yokoyama
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $457,803
- **Award type:** 2
- **Project period:** 2015-07-01 → 2024-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10058693

## Citation

> US National Institutes of Health, RePORTER application 10058693, Mechanism of carbon skeleton formation in molybdenum cofactor biosynthesis (2R01GM112838-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10058693. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*