To rationalise these observations, virtual dockings were carried out on SFs 2d and 2e, based on the reported binding mode of ethoxzolamide (PDB: 3CAJ). For 2e, the docking indicated that the sulfonamide was bound to the Zn 2+ cofactor, and the His64 residue was proximal to the SF group, just 7 Å away, and appears well poised for reaction (Fig. ). Similarly, for 2d, the Zn 2+ -sulfonamide interaction was observed, and the SF group was in the vicinity of His64, as well as residues His3 and Tyr7 which were also found to carry minor modifications (see Fig. ).