Fig. 7

Composite model of feline APOBEC3 and locations of residues mediating Vif binding. a Structural model of FcaA3Z2Z3 including the linker (pink) at a putative location above the Z2 (yellow) and Z3 (blue) domains; the linker connections to the Z2 and Z3 domains are highlighted by dashed lines. [69]. b Structural model of FcaA3Z2Z3 rotated by 90° with respect to a (Z2 domain: yellow; Z3 domain: blue; the linker region and parts of the N-terminus of Z2 and the C-terminus of Z3 for which no structure could be modeled were omitted for clarity). Residues in sphere representation in yellow (D165/H166), those in blue (L285/I286/A309), and those in orange (D131-Y134). Residues sequentially equivalent to the latter in the soluble N-terminal Vif-binding domain (sNTD) of A3G (PDB ID 2MZZ; pale green) are colored in green; these residues are part of the Vif-binding regions of the sNTD [68]. c Crystal structure of human A3C (PDB ID: 3VOW) and structural model of feline A3Z2b depicting the positions of respective HIV-1 Vif and FIV Vif binding sites. The domains are orientated as the Z2 domain in a. d Structural model of human A3H-HapII and feline A3Z3 depicting the positions of respective HIV-1 Vif and FIV Vif binding sites. The domains are orientated as the Z3 domain in a. Key residues involved in Vif binding are labelled (except human A3C), represented in sticks and highlighted with its surface in orange color