Fig. 3. Electrostatic potential surface maps of the VP22_core dimer. (a) The positive, negative and uncharged regions of the surface map are coloured blue, red and white, respectively. The protein is shown in the same orientation as in Fig. 1(b). It reveals a patch of positive charges in the middle of a relatively uncharged surface. Flanking their sides are areas of negatively charged patches. (b) At the groove side, there are two large positively charged patches. The charges on this surface are contributed by the α1 amino acids lining the groove. The protein is shown in the same orientation as in Fig. 1(d). (c) The positively charged patch at the peak side is created by Arg242, whilst (d) the negatively charged patch is created by Asp186 from L1 of one monomer and a cluster of negatively charged residues, Glu230, Asp231 and Glu234, from α2 of the second monomer. These distinctively charged patches on VP22_core might be potential molecular interaction sites.