Figure 1
(a) The CATPO tetramer shown as a ribbon diagram, highlighting the heme and 3TR binding sites. The heme is colored red, 3TR in the oxidase pocket is colored pink and 3TR at the dimer interface is colored orange. (b) The 3TR binding site in the lateral channel of CATPO. Composite OMIT electron density, calculated using the CCP4 COMIT program (Winn et al., 2011), for 3TR and bound waters is drawn at 1 r.m.s.d. and shown as a blue wire mesh. Analysis of the hydrogen bonding suggests that 3TR is bound as 2H-1,2,4-triazole-3-amine and at the pH of the crystals should be in its neutral form. (c) View of chain A of the CATPO complex with 3TR (PDB entry 5zz1; grey) superposed onto human catalase (PDB entry 1dgh; blue). CATPO loop 533–537 lies across the top of the NADPH-binding pocket, clashing with the position of the NADPH in the human enzyme. |