Membrane action of synthetic N-terminal peptides of influenza virus hemagglutinin and its mutants.

Synthetic peptides corresponding to the N-terminal of the cleaved hemagglutinin (HA2) of influenza virus induce an increase in conductance of planar phospholipid bilayers, and cause the release of encapsulated molecules from large unilamellar liposomes. Two mutant peptides, derived from hemagglutinins of mutant viruses with no or reduced fusion activity, do not alter the membrane conductance significantly. These observations support the hypothesis that influenza virus fuses with its target membrane by inserting the HA2 N-terminal into the membrane.