Figure 7
(a) A superposition (CHIMERA)28 of the EcHpaB and XS6 structures highlighting the active site (cyan: the active site of the EcHpaB and purple: active site of the XS6). The superposition gave an R.M.S.D of 0.323 Å for 509 Cα pairs. (b) A model of the XS6 β32-β33 loop structure (residues 206–220) showing the electron density observed in this region (CCP4MG)47. The model was generated by superposition28 of the native and XS6 EcHpaB structures with the coordinates for the EcHpaB loop residues 206–220 mutated (COOT)43 to correspond to residues in the XS6 mutant. The (2Fo-Fc) electron density map (contoured at 1 σ) for this region shows a lack of electron density for residues 208–216 of the β32-β33 loop. This missing density is consistent with a highly flexible loop which was the aim of the XS6 mutant design. (Color key: carbon-gray, nitrogen-blue, oxygen-red and electron density-blue).
