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Membrane fusion mediated by coiled coils: a hypothesis.
1Department of Bioscience and Biotechnology, Drexel University, Philadelphia, Pennsylvania 19104-2875, USA. bentzj@drexel.edu
Biophysical Journal
|February 2, 2000
Summary
Influenza hemagglutinin (HA) mediates viral fusion by forming a hydrophobic membrane defect. A model proposes that HA aggregates create this defect, initiating membrane fusion by recruiting target membrane lipids.
Area of Science:
- Biophysics
- Virology
- Molecular Biology
Background:
- Influenza hemagglutinin (HA) mediates low-pH-induced membrane fusion.
- Fusion requires HA aggregates, but only a subset undergoes essential conformational changes.
- Initial fusion pore formation restricts lipid flow.
Purpose of the Study:
- Propose a molecular model for low-pH-induced membrane fusion by influenza hemagglutinin (HA).
- Explain the role of HA conformational changes and aggregate formation in membrane fusion.
Main Methods:
- Molecular modeling based on existing experimental data.
- Hypothesis-driven analysis of HA aggregation and conformational changes.
Main Results:
- A tightly packed HA aggregate with inserted fusion peptides initiates fusion.
- Conformational changes in a subset of HA create a stabilized hydrophobic membrane defect.
- This defect drives fusion by recruiting lipids from the target membrane.
Conclusions:
- The proposed model explains HA-mediated membrane fusion through hydrophobic defect formation.
- The model is consistent with observations on HA aggregation and lipid flow.
- The hypothesis may apply to other viral fusion proteins and SNARE complexes.