DYNAMIC PROPERTIES OF NEWCASTLE-DISEASE-VIRUS ENVELOPE AND THEIR RELATIONS WITH VIRAL HEMAGGLUTININ-NEURAMINIDASE MEMBRANE GLYCOPROTEIN

The lipid composition of Newcastle Disease Virus (NDV) Clone-30 strain shows a low lipid/protein ratio, a high cholesterol/phospholipid mola r ratio, and major phospholipids being qualitatively different to othe r NDV strains. The major fatty acyl constituents are palmitic, stearic , oleic, and linoleic acids; cerebrosides, sulfatides and two kinds of gangliosides are also found in the NDV membrane. It is reported for t he first time in NDV that phospholipid classes are asymmetrically dist ributed over the two leaflets of the membrane: 60 +/- 4.5% of the phos phatidylcholine and 70 +/- 5.0% of the sphingomyelin are in the outer monolayer. Intact viral membranes and reconstituted NDV envelopes show ed similar dynamic properties. Hemagglutinin-neuraminidase (HN) and fu sion (F) proteins of NDV membrane affect the lipid thermotropic behavi our in reconstituted proteoliposomes made up of a single class of phos pholipids. It is shown that the lipid composition is more important th an the bulk membrane fluidity/order for both sialidase (neuraminidase) and hemagglutinating HN activities. Sialidase and hemagglutinating ac tivities requires the presence of definite phospholipids (phosphatidyl ethanolamine) in its environment. (C) 1997 Elsevier Science B.V.