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Updated: Mar 12, 2026

A Fluorogenic Peptide Cleavage Assay to Screen for Proteolytic Activity: Applications for coronavirus spike protein activation
Published on: January 9, 2019
Three conserved C-terminal residues of influenza fusion peptide alter its behavior at the membrane interface
Remigiusz Worch1, Joanna Krupa1, Alicja Filipek1
1Institute of Physics, Polish Academy of Sciences, Poland.
Abstract:
The N-terminal fragment of the viral hemagglutinin HA2 subunit is termed a fusion peptide (HAfp). The 23-amino acid peptide (HAfp1-23) contains three C-terminal W21-Y22-G23 residues which are highly conserved among serotypes of influenza A and has been shown to form a tight helical hairpin very distinct from the boomerang structure of HAfp1-20. We studied the effect of peptide length on fusion properties, structural dynamics, and binding to the membrane interface. We developed a novel fusion visualization assay based on FLIM microscopy on giant unilamellar vesicles (GUV). By means of molecular dynamics simulations and spectroscopic measurements, we show that the presence of the three C-terminal W21-Y22-G23 residues promotes the hairpin formation, which orients perpendicularly to the membrane plane and induces more disorder in the surrounding lipids than the less structured HAfp1-20. Moreover, we report cholesterol-enriched domain formation induced exclusively by the longer fusion peptide.
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