# MODULATION OF MEMBRANE FUNCTION BY COMPLEMENT

> **NIH NIH R01** · UNIVERSITY OF FLORIDA · 1989 · $145,407

## Abstract

The long range objectives of the proposed research are to
characterize the nature and the extent of interaction between the
terminal complement proteins (C5, C6, C7, C8, C9), which
together form the membrane attack complex (MAC) of
complement, and lipids and proteins in artificial and natural
target membranes.  We want to understand the mechanism of
assembly of this complex on a cell's surface and elucidate the
mechanisms through which the MAC can either cause immune
cytolysis and cell death or protect host cells from auto-
destruction.

We expect to attain our long range goals by using a combination
of biophysical, biochemical and immunochemical techniques to
investigate the assembly of the MAC and its effect on the target
membrane.  Our studies will focus predominantly on C9 because
this protein provides the main lytic and cytotoxic functions of the
MAC.  We will use the synthetic peptide approach to generate an
epitope map of native C9 and of C9 when bound to target
membrane.  Circular dichroism and electron spin resonance (ESR)
spectroscopy will be used to analyze conformational changes in
the protein as they assemble on and penetrate into the membrane.
The corresponding changes in lipid bilayer structure will be
monitored by ESR and differential scanning calorimetry.  The
resulting MAC-membrane complex will visualized by freeze-
fracture electron microscopy.  Localization of the active center
of C9 will be attempted by producing proteolytic fragments with
lytic or cytotoxic activity.  Such activities will be assayed by
measuring release of markers from liposomes, or changes in
conductance across planar lipid bilayers, and by testing peptides
directly for their effects on survival of blood cells and bacteria.

## Key facts

- **NIH application ID:** 3128824
- **Project number:** 5R01AI019478-08
- **Recipient organization:** UNIVERSITY OF FLORIDA
- **SAM.gov UEI:** NNFQH1JAPEP3
- **Principal Investigator:** ALFRED F ESSER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1989
- **Award amount:** $145,407
- **Award type:** 5
- **Project period:** 1982-04-01 → 1992-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3128824

## Citation

> US National Institutes of Health, RePORTER application 3128824, MODULATION OF MEMBRANE FUNCTION BY COMPLEMENT (5R01AI019478-08). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3128824. Licensed CC0.

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