Nucleotide sequence of the gene encoding the Newcastle disease virus hemagglutinin-neuraminidase protein and comparisons of paramyxovirus hemagglutinin-neuraminidase protein sequences.

The nucleotide sequence of cloned cDNA copies of the mRNA encoding the Newcastle disease virus (NDV), strain A-V, hemagglutinin-neuraminidase (HN) protein was determined. A single open reading frame in the sequence encodes a protein of 570 amino acids with a calculated molecular weight of 62,280. The predicted protein sequence contains only one obvious potential membrane spanning region, located 27 amino acids from the amino terminus of the sequence. The predicted sequence contains 6 glycosylation sites and 14 cysteine residues. Comparison of the NDV HN protein sequence with three other paramyxovirus HN protein sequences reveals two regions that have homologies in all four sequences. The conserved cysteine residues are clustered in these two regions. One conserved region is located near the middle of the predicted sequence while the second region is in the carboxy terminal third of the molecule. The presence of conserved regions suggests the importance of these areas of the molecule in the structure or function of the protein.