Figure 16.

(A) The crystal structure of the truncated glycoprotein E2 shown in green in ribbon representation with fragments containing the predicted binding sites in yellow and magenta, as well as a conserved region in cyan (PDB id: 6MEH).¹⁵⁷ (B) Amino acid residues crucial for the E2-CD81 interaction, presented as sticks colored according to atom type.¹⁵⁸ (C) The interaction between tamarin CD81 (pink) and E2 (green) with the interacting residues carbon atoms’ colors matching the ribbon color of the same chain (PDB id: 7MWX).¹⁵⁹ (D) The full structure of human tetraspanin CD81 in the closed conformation, including the transmembrane helices with a cholesterol binding pocket.¹⁶⁰ The large extracellular loop is highlighted in pink (PDB id: 5TCX).¹⁶⁰