The interaction of synthetic analogs of the N-terminal fusion sequence of influenza virus with a lipid monolayer. Comparison of fusion-active and fusion-defective analogs

• Published in: Biochimica et biophysica acta Vol. 1065; no. 2; pp. 121 - 129
• Main Authors: Burger, K N, Wharton, S A, Demel, R A, Verkleij, A J
• Format: Journal Article
• Language: English
• Published: Netherlands 18.06.1991
• Subjects: Amino Acid Sequence; Circular Dichroism; Hemagglutinin Glycoproteins, Influenza Virus; Hemagglutinins, Viral - chemistry; Hemagglutinins, Viral - physiology; Membrane Fusion; Membrane Lipids - physiology; Molecular Sequence Data; Peptide Fragments - chemistry; Peptide Fragments - physiology; Pressure; Protein Conformation; Surface Properties
• ISSN: 0006-3002
• DOI: 10.1016/0005-2736(91)90221-S

The amino terminus of subunit-2 of influenza virus hemagglutinin (NHA2) plays a crucial role in the induction of fusion between viral and endosomal membranes leading to the infection of a cell. Three synthetic analogs with an amino acid sequence corresponding to NHA2 of variant hemagglutinins were studied in a monolayer set up. Comparison of the interaction of a fusion-active and two fusion-defective analogs with a lipid monolayer revealed a greater surface activity of the fusion-active analog. Pronounced differences were found if the pure peptides were spread at the air/water interface; the fusion-active analog showed a higher collapse pressure and a greater limiting molecular area. Circular dichroism measurements on collected lipid monolayers indicated a high content of alpha-helical structure for the fusion-active and one of the fusion-defective analogs. A simple relation between alpha-helical content and fusogenicity does not seem to exist. Instead, the extent of penetration, a defined tertiary structure or orientation of the alpha-helical peptide may be essential for its membrane perturbing activity.