Amino acid substitutions contributing to α2,6-sialic acid linkage binding specificity of human parainfluenza virus type 3 hemagglutinin-neuraminidase.

Human parainfluenza virus type 3 (hPIV3) recognizes both α2,3- and α2,6-linked sialic acids, whereas human parainfluenza virus type 1 (hPIV1) recognizes only α2,3-linked sialic acids. To identify amino acid residues that confer α2,6-linked sialic acid recognition of hPIV3, amino acid residues in or neighboring the sialic acid binding pocket of the hPIV3 hemagglutinin-neuraminidase (HN) glycoprotein were substituted for the corresponding residues of hPIV1 HN. Hemadsorption assay with sialyl linkage-modified red blood cells indicated that amino acid residues at positions 275, 277, 372, and 426 contribute to α2,6-linked sialic acid recognition of the HN3 glycoprotein.