# COORDINATION CHEMISTRY OF MICROBIAL IRON TRANSPORT

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA BERKELEY · 1992 · $181,069

## Abstract

Although iron is the most abundant transition metal in the earth's curst it
is highly inaccessible under ambient conditions because of the insolubility
of Fe(OH)3.  In response to the challenge posed by iron requirement and
unavailability, microorganisms secrete high-affinity iron-binding compounds
called siderophores with several types of chemical structures found among
the more than 100 compounds characterized to data.  Siderophores solubilize
ferric ion and enable it to be transported into cells, usually via specific
membrane-bound uptake systems.  This process involves a highly
stereospecific recognition of the ferric complex by receptor proteins at
the cell surface.  Examination of the solution conformations and geometries
of these iron-complexing agents is made possibly by the preparation of
exchange inert metal complexes.  Fundamental data on solution
thermodynamics, kinetics, and electrochemistry are determined to examine
iron release mechanisms.  The application of Mossbauer spectroscopy in vivo
allows direct monitoring of iron assimilation via siderophores.

Specific goals are:  to determine the stereochemical specificity of
siderophore recognition and transport using exchange inert metal complexes
and synthetic siderophore analogs; to categorize siderophore-mediated iron
transport; to characterize new siderophores, their structures, physical
properties and transport behavior; to examine the fundamental thermodynamic
features of siderophores; to examine relative rates of metal complexation
and exchange for siderophores and transferrins to determine whether such
removal is a pathway for iron uptake by potential pathogens; to understand
the electronic structure of these high-spin d5 systems so that the VIS/UV
and CD spectra of the native siderophore iron complexes can be used more
effectively in structure and composition assignment.

Iron availability is a key factor in the virulence of microbial infections.
Siderophores have been identified as germination or sporulation factors for
several organisms and human pathogens obtain iron from tissues or sera by
producing siderophores.  Diseases in which direct involvement of
siderophores has been established include infantile enteritis, leprosy, and
tuberculosis.  Iron transport is now known to be essential in the growth of
many food plants (and their pathogens) as well as in the growth of
phytoplankton (the base of the marine food chain).  The focus of this
research project remains the coordination chemistry aspects of siderophore
mediated iron transport in bacteria and fungi.

## Key facts

- **NIH application ID:** 3125023
- **Project number:** 5R01AI011744-18
- **Recipient organization:** UNIVERSITY OF CALIFORNIA BERKELEY
- **SAM.gov UEI:** GS3YEVSS12N6
- **Principal Investigator:** KENNETH N RAYMOND
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1992
- **Award amount:** $181,069
- **Award type:** 5
- **Project period:** 1976-04-01 → 1996-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3125023

## Citation

> US National Institutes of Health, RePORTER application 3125023, COORDINATION CHEMISTRY OF MICROBIAL IRON TRANSPORT (5R01AI011744-18). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3125023. Licensed CC0.

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