# IMMUNITY PROTEIN AND CHANNEL DOMAIN OF COLICIN EL

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA LOS ANGELES · 1988 · $110,304

## Abstract

The long term objective is to understand the mode of action of colicin E1
immunity protein which protects bacteria against colicin killing.
Purification of the immunity protein may allow the development of an in
vitro assay for its activity.  Because of its low abundance, cloning of the
immunity protein into high expression vectors has been completed.
Over-production of the cloned protein in a consistent manner will be
systematically pursued.  Specific antibodies that recognize the immunity
protein will be further purified from the total immunoglobulin fraction
which is immunoblot positive.  Additional antibodies against synthetic
peptides corresponding to the hydrophilic domains of the immunity protein
will be prepared if needed.  These antibodies will be used to purify the
immunity protein by affinity chromatography in conjunction with more
conventional protein purification techniques.  Antibodies against the
synthetic peptides will be used to probe the membrane topography of the
protein by immunofluorescence and electron microscopy in bacterial
vesicles.  A new fluorescence assay will be used to test the possible
activity of the purified immunity protein in reconstituted liposomes
against colicin channels.  Binding, proteolytic cleavage or chemical
modification will be explored as possible modes of channel inactivation.
Temperature-sensitive immunity mutants will be screened for after in vitro
mutagenesis of the plasmid.  Colicin E1 fragments generated by the genetic
manipulation of the Col E1 plasmid will be tested for channel activity in
liposomes.  The molecularities of other E1-type colicins (K, A, Ia and Ib)
will be determined with a new stopped-flow ion-flux assay.

## Key facts

- **NIH application ID:** 3128027
- **Project number:** 5R01AI018578-06
- **Recipient organization:** UNIVERSITY OF CALIFORNIA LOS ANGELES
- **SAM.gov UEI:** RN64EPNH8JC6
- **Principal Investigator:** CELIK KAYALAR
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $110,304
- **Award type:** 5
- **Project period:** 1987-09-01 → 1989-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3128027

## Citation

> US National Institutes of Health, RePORTER application 3128027, IMMUNITY PROTEIN AND CHANNEL DOMAIN OF COLICIN EL (5R01AI018578-06). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3128027. Licensed CC0.

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