Fusion of a Sendai mutant deficient in HN protein (ts271) with cardiolipin liposomes.
Sendai mutant ts271 contains less than 5% of the amount of HN glycoprotein found in wild-type Sendai. Fusion of this mutant with cardiolipin liposomes revealed no differences from the wild-type virus with regard to specific activity, pH dependence, or radiation inactivation. Target sizes of both mutant and wild-type viral proteins were determined by the radiation-induced disappearance of each band from an SDS-polyacrylamide gel and no differences were found. Of the viral proteins, only F had a target size corresponding to the monomer molecular weight, ca. 60 kDa, identical to the minimum unit previously determined by functional assay for Sendai virus-erythrocyte membrane fusion (K. Bundo-Morita, S. Gibson, and J. Lenard, Biochemistry 26, 6223-6227 (1987)). This provides additional evidence that F alone is the active protein mediating Sendai-erythrocyte fusion. It is concluded that the HN protein is unlikely to mediate any fusion reactions of the intact virions, either with biological membranes or with cardiolipin liposomes.
Gibson
S
S
Department of Physiology and Biophysics, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854.
Bundo-Morita
K
K
Portner
A
A
Lenard
J
J
D002308:Cardiolipins; D004229:Dithiothreitol / Q000494:pharmacology; D015707:HN Protein; D006863:Hydrogen-Ion Concentration; D008081:Liposomes; D008970:Molecular Weight; D009154:Mutation; D010222:Parainfluenza Virus 1, Human / Q000187:drug effects / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D013696:Temperature; D014759:Viral Envelope Proteins / Q000502:physiology*; D014760:Viral Fusion Proteins / Q000502:physiology*
D002308:Cardiolipins; D015707:HN Protein; D008081:Liposomes; D014759:Viral Envelope Proteins; D014760:Viral Fusion Proteins; D004229:Dithiothreitol