In the paramyxoviruses, cleavage of the F0 protein into two subunits F1 and F2 is important for which of the following? glycosylation of the protein creation of the transmembrane domain formation of the envelope exposing the fusion peptide Solution Answer: D. exposing the fusion peptide Explanation: Paramyxoviruses contain two membrane glycoproteins, the fusion protein (F) and the hemagglutinin-neuraminidase protein (HN). The F protein is synthesized as an uncleaved, inactive form (F0) and is cleaved into F1 and F2 subunits. Cleavage of the F protein by a trypsin- like protease is required for virus infectivity. The exposure of a new hydrophobic domain at the N terminus of the F1 subunit appears to be essential for the membrane fusion activity of the F protein. The other glycoprotein, HN, binds to sialic acid-containing receptors and possesses neuraminidase activity..