Functional analysis of the N-linked glycans within the fusion protein of respiratory syncytial virus.

The respiratory syncytial virus fusion (F) protein is initially expressed as a single polypeptide chain (F0). The F0 subsequently undergoes posttranslational cleavage-by-cell protease activity to produce the F1 and F2 subunits. Each of the two subunits within the mature F protein is modified by the addition of N-linked glycans. The individual N-linked glycans on the F protein were selectively removed by using site-directed mutagenesis to mutate the individual glycan-acceptor sites. In this way the role of these individual glycans in targeting of the F protein to the cell surface, and on the ability of the F protein to induce membrane fusion, was examined.