# INTERACTION OF COLICIN I WITH ESCHERICHIA COLI

> **NIH NIH R01** · UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN · 1988 · $134,533

## Abstract

Colicins Ia and Ib are structurally related protein toxins produced by E.
coli strains harboring the pCo1Ia and pCO1Ib plasmids.  These toxins are
active against certain E. coli strains which they kill by forming aqueous
channels in the bacterial cytoplasmic membrane.  Strains which produce
colicin Ia are insensitive to this colicin, but sensitive to colicin Ib,
and vice versa.  This property, called immunity, is determined by the same
plasmid which encodes the colicin.

This proposal extends our previous work on the Ia/Ib system and focuses on
three distinct areas:  (a) a determination of the amino acid sequence of
these toxins, (b) a delineation of the mechanism of immunity, and (c)
elucidation of the mechanism whereby expression of the gene which encodes
the colicin Ia/Ib receptor, a component of the outer membrane of sensitive
cells, is regulated by iron.

The primary sequence of both colicins will be deduced from the nucleotide
sequence of their cloned genes.  For studies on immunity, we will purify
both the pCo1Ia- and pCo1Ib-determined immunity proteins.  The ability of
each to form a complex with pure colicins will be ascertained.  Interaction
of homologous, but not heterologous pairs, would support our hypothesis
that immunity results from specific recognition between homologous pairs
with subsequent neutralization of colicin activity.

To study regulation of receptor synthesis, regulatory mutants will be
isolated and characterized.  Mutant and wild type genes will be cloned and
sequenced.  This approach will allow identification of genetic elements
controlling expression of the receptor gene.  Since the colicin Ia/Ib
receptor may have a physiological function in iron uptake, an understanding
of the way its production is regulated by iron may provide insights into
the regulation of iron uptake.

## Key facts

- **NIH application ID:** 3124651
- **Project number:** 5R01AI010106-18
- **Recipient organization:** UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
- **SAM.gov UEI:** Y8CWNJRCNN91
- **Principal Investigator:** JORDAN KONISKY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $134,533
- **Award type:** 5
- **Project period:** 1979-02-01 → 1989-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3124651

## Citation

> US National Institutes of Health, RePORTER application 3124651, INTERACTION OF COLICIN I WITH ESCHERICHIA COLI (5R01AI010106-18). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3124651. Licensed CC0.

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