# MECHANISMS OF MICROBIAL IRON TRANSPORT

> **NIH NIH R01** · UTAH STATE UNIVERSITY · 1987 · $80,977

## Abstract

The objective of this research is to understand the detailed molecular
mechanisms by which microorganisms sequester iron.  Research in this area
has previously concentrated on a group of compounds, called siderophores,
which chelate ferric ion and transport it into the cells via specific
transport systems.  However, it is well known that microorganisms can also
assimilate the metal from a wide variety of other complexes, such as citric
acid and siderophores from non-related organisms.  Recent work in our
laboratory strongly suggests that often this non-specific uptake involves
reduction of the metal to the ferrous state followed by translocation of
the metal into the cell with the organic ligand remaining extracellular.
Virtually nothing is known about the detailed mechanism of this process.
This research would establish the reductive mechanism as general in the
microbial kingdom and address questions of the specificity of the system,
i.e., can other metals be reduced and is iron octahedrally coordinated to
oxygen ligands required.  What is the source of electrons for the
extracellular reduction?  Are membrane-associated ferrireductases
involved?  Isotopic iron will be complexed to a variety of organic ligands
and tested with several unrelated organisms to establish the generality of
the process.  An appropriate organism, probably E. coli, will be chosen to
examine the details.  Membrane preparations will be examined for their
ability to reduce ferric chelates, and the enzyme responsible will be
purified.  We will also examine the possibility that fungal esterases,
which have been shown to be sensitive to sulfhydryl reagents, act as
ferrireductases in the presence of an electron source.  There is increasing
evidence that iron acquisition plays an important role in the course of
bacterial and fungal infections in man, and for this reason research in the
role of siderophores in microbial iron transport has become increasingly
clinically relevant.  However, the finding that microorganisms possess a
reductive mechanism of iron transport, which enables them to obtain iron
from a host of chelates, puts this area of research in a new light.  If
chemotherapy based on depriving infecting microorganism of irons is to be
truly effective, it will be necessary to understand the mechanism of the
reductive transport system also.

## Key facts

- **NIH application ID:** 3124584
- **Project number:** 5R01AI009580-15
- **Recipient organization:** UTAH STATE UNIVERSITY
- **SAM.gov UEI:** SPE2YDWHDYU4
- **Principal Investigator:** THOMAS F. EMERY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $80,977
- **Award type:** 5
- **Project period:** 1978-09-01 → 1989-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3124584

## Citation

> US National Institutes of Health, RePORTER application 3124584, MECHANISMS OF MICROBIAL IRON TRANSPORT (5R01AI009580-15). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3124584. Licensed CC0.

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