FIG. 1.

ALSV putative fusion peptide region. (A) Overlay of the hydropathy plots of the TM subunits of Env glycoproteins of subgroups A (Schmidt-Ruppin), C (Prague), D (Schmidt-Ruppin), and E (RAV-0) ALSV. Arrow points to the candidate fusion peptide region. ∗, TM domain. (B) Amino acid sequence of the candidate fusion peptide region in four ALSV subgroups. •, identical amino acid at that position. (C) Putative fusion peptide region of ALSV-A modeled as an alpha helix. The hydrophobic face is outlined and has an average hydrophobicity index of 1.01. The position 1, 2, and 3 amino acids are circled. As discussed in the text, this region may adopt other structures either before or during fusion.