# Nitrogenase assembly mechanism

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA-IRVINE · 2020 · $306,839

## Abstract

PROJECT SUMMARY
Nitrogenase reaction represents a major source of the usable form of nitrogen that supports the
existence of human population. As such, understanding how small building blocks are
assembled into a functional nitrogenase entity is of significant relevance to human health. Using
combined genetic, biochemical, spectroscopic and structural approaches, we propose to
investigate how M- and P-clusters of molybdenum nitrogenase are assembled via unique
biochemical reactions into functional units. Specifically, we will investigate how two 4Fe
modules are rearranged and coupled into an 8Fe core of M-cluster via radical SAM-dependent
carbide insertion concomitant with the incorporation of a “9th” sulfur, how two 4Fe modules are
rearranged and coupled into an 8Fe P-cluster via unique redox reactions concomitant with the
removal of an “8th” sulfur, and how various assembly proteins interact with one another to
facilitate the maturation of M- and P-clusters. Through our proposed studies, we expect to
further refine the biosynthetic pathways of the unique metalloclusters of nitrogenase, which will
provide crucial insights into the structural-functional relationship of this important enzyme and
reveal some general principles of the assembly mechanisms of complex metalloclusters in
biological systems.

## Key facts

- **NIH application ID:** 9829577
- **Project number:** 5R01GM067626-17
- **Recipient organization:** UNIVERSITY OF CALIFORNIA-IRVINE
- **Principal Investigator:** Markus W Ribbe
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $306,839
- **Award type:** 5
- **Project period:** 2003-05-01 → 2020-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9829577

## Citation

> US National Institutes of Health, RePORTER application 9829577, Nitrogenase assembly mechanism (5R01GM067626-17). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9829577. Licensed CC0.

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