Three conserved C-terminal residues of influenza fusion peptide alter its behavior at the membrane interface.
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.
Institute of Physics, Polish Academy of Sciences, Poland. Electronic address: remiwo@ifpan.edu.pl.
Remigiusz
R
Worch
Institute of Physics, Polish Academy of Sciences, Poland.
Joanna
J
Krupa
Institute of Physics, Polish Academy of Sciences, Poland.
Alicja
A
Filipek
Institute of Physics, Polish Academy of Sciences, Poland.
Anna
A
Szymaniec
Centre for New Technologies, University of Warsaw, Poland.
Piotr
P
Setny
D000596:Amino Acids / Q000378:metabolism; D017124:Conserved Sequence / Q000502:physiology; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000378:metabolism*; D009980:Influenza A virus / Q000378:metabolism*; D008051:Lipid Bilayers / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology*; D008566:Membranes / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D010446:Peptide Fragments / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D011487:Protein Conformation
D000596:Amino Acids; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D008051:Lipid Bilayers; D010446:Peptide Fragments; D010455:Peptides
Confocal microscopy; Fluorescence; Giant unilamellar vesicles; Influenza virus; Lifetime imaging microscopy; Molecular simulations; Peptide-lipid interactions