The Secret Life of Viral Entry Glycoproteins: Moonlighting in Immune Evasion
Figure 2
Structural conservation of the viral glycoprotein immunomodulatory region.
The immunomodulatory region is approximately 20 amino acids long and is found within numerous retroviruses and filoviruses. In each case presented here, the experimentally defined immunomodulatory region is rendered in yellow and residues that are necessary for the observed immunomodulatory activity are depicted as spheres. (A) Head-on view of viral glycoproteins exhibiting a conserved three-fold pinwheel structure. (B) Side-view illustrating the differences in possible interaction faces between the lentiviral gp41 immunomodulatory region and a representative retrovirus, HTLV-1. The outward positioning of the important immunomodulatory residues shown for HTLV-1 gp21 can be observed in all available retroviral and filoviral post-fusion glycoprotein structures except SIV gp41. The PDB codes for the fusion glycoproteins are as follows: EBOV GP2, 2EBO; MARV GP2, 4G2K; HTLV-1 gp21, 1MG1; syncytin-2, 1Y4M; SIV gp41, 2EZO.