Functional analysis of a conserved region of the baculovirus envelope fusion protein, LD130.

The envelope fusion protein from a baculovirus pathogenic for Lymantria dispar was characterized. N-terminal sequence analysis determined that it was cleaved downstream of predicted signal peptide and furin cleavage motifs. Mutation of the furin motif resulted in a protein that was not cleaved and did not mediate fusion. Mutagenesis of three charged amino acids in a conserved sequence with the features of a fusion peptide resulted in significant reduction of the ability of the constructs to mediate fusion. None of the mutations inhibited transport of the proteins to the cell surface. In addition, the mutations of the predicted fusion peptide region yielded no inhibition of cleavage. No difference in cleavage was detected between constructs expressed in Spodoptera frugiperda or L. dispar cells.