Structure of AFV3-109 monomer and dimer. A) Monomer presentation of AFV3-109. Secondary structure elements are labelled according to Figure 2. B,C) Two perpendicular representations of the AFV3-109 dimer (monomers are coloured bleu and deep red). Bound glycerol is shown as in green and red sticks. D) Superposition of AFV3-109 (blue) and B116 (red) dimers highlighting the conformational difference of the β4β5 connexion in both proteins. E) Architectural similarities between AFV3-109 and eukaryotic viral transcriptional regulators: ribbon representation of papilloma virus E2 (PDB code: 1JJH) and EBNA1 Epstein Barr Virus (PDB code: 1VHI) dimers. F) Stereo view of the 2fo-fc residual density in front of the conserved His45, modeled by a glycerol moiety (in sticks). Hydrogen bonds are represented by dashed lines, bound waters as spheres. Residues from both monomers are labeled A and B. G) Electrostatic potential surface of the AFV3-109 dimer (same orientation as in A). H) Electrostatic potential surface of an 'open' configuration of the AFV3-109 dimer, modeled on the B116 dimer structure, revealing a strongly positively charged surface inside the cavity.