[Membrane structure of remantadine-sensitive and remantadine-resistant influenza virus studied with fluorescent...

Significant differences in the molecular organization of lipid bilayer in remantadin-resistant and remantadin-sensitive strains of influenza virus were demonstrated by means of fluorescent phospholipid probes, analogues of phosphatidylcholine and sphingomyelin. The data on fluorescence polarization and transfer of excitation energy from protein tryptophanes on probe fluorophores showed phosphatidylcholine and sphingomyelin to be segregated in influenza virion membrane. Gradients of mobility of lipid chains in virion membrane and in phospholipid vesicles have opposite directions. The results indicate that M protein coming inside virion into contact with the lipid bilayer does not penetrate further than its middle. In virions of the resistant strain remantadin destroys the array of the entire bilayer whereas in the sensitive strain the addition of remantadin results in a marked decrease of mobility of the chains in the surface area. It is suggested that the molecular organization of lipids is one of the factors determining influenza virus sensitivity to remantadin.