Figure 5: Surface electrostatic potential of APOBEC3 proteins.

A negatively charged surface conserved with other Z2-cytosine deaminase domains is proposed to be important for Vif-binding. Electrostatic potential mapped onto the molecular surface of A3C (PDB: 3VOW), and the homology models of A3D-CD2, A3G-CD1 and A3H. The proposed footprints of the A3 negative and hydrophobic patch involved in Vif binding are shown by the solid and dashed lines, respectively. A previously characterized ‘DPD’ motif involved in A3G Vif binding is displayed for the A3G-CD1 homology model. Red and blue coloured regions denote negative and positive charges, respectively. Note: the ssDNA-binding site is at the top of the depicted A3 molecules and has no overlap with the hydrophobic or negatively charged Vif-binding site.