The Subunit Structure of Influenza Virus Envelope Protein

Abstract

Abstract The influenza virus particle is surrounded by a lipid-protein envelope from which spike-like projections protrude. There is evidence that the major surface structural antigen is located in these projections (1). In an earlier report (2), procedures for obtaining envelope protein in a soluble form were described. Virus concentrates were extracted first with methanol-chloroform and the residue was treated with 8 m urea and 0.01 m dithiothreitol. In this solvent the envelope protein was reduced to chemical subunits, which, on removal of the dissociating reagent by dialysis, assembled into a uniform protein with a sedimentation constant of 4 S. A specific serologic relationship was demonstrated by complement fixation and blocking antigen tests between the homogeneous protein preparation and the strainspecific surface antigen of the viral envelope (2). The present report is concerned with attempts to obtain envelope protein in a more highly purified state and to determine by acrylamide gel electrophoresis the number of polypeptide components associated with the preparations.