Intracellular maturation of the Newcastle disease virus fusion protein is affected by strain differences in the predicted amphipathic alpha-helix adjacent to the fusion domain.
The fusion (F) glycoprotein of Newcastle disease virus (NDV) contains a predicted amphipathic alpha-helix C-terminal to its fusion domain. Of the 13 available NDV F protein sequences, only the Australia-Victoria (AV) strain alpha-helix is weakened, by the replacement of Ala159 with Thr. In this report, we demonstrate that the efficiency of cleavage and virion incorporation of the AV F protein, unlike that of other strains, is temperature sensitive. Pulse/chase experiments at 42 degrees revealed disulfide-linked aggregates containing both the F and hemagglutinin-neuraminidase glycoproteins in strain AV, but not in strain Beaudette C. Furthermore, a revertant derived from AV, whose helix-weakening Thr159 has been replaced with the consensus Ala, produced fewer F protein aggregates, confirming the structural importance of this region in maturation. In addition, a novel disulfide-defined folding intermediate of the F protein was detected.
Wang
C
C
Department of Immunology/Microbiology, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA.
Peeples
M E
ME
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D005347:Fibroblasts; D015707:HN Protein / Q000032:analysis; D009522:Newcastle disease virus / Q000378:metabolism*; D017510:Protein Folding; D011499:Protein Processing, Post-Translational; D017433:Protein Structure, Secondary; D013696:Temperature; D014760:Viral Fusion Proteins / Q000737:chemistry* / Q000378:metabolism*; D014771:Virion / Q000378:metabolism
D000596:Amino Acids; D015707:HN Protein; D014760:Viral Fusion Proteins