    2.4.2.19 | PDB code: 2jbm (apo-hQPRTase), alpha/beta barrel fold (12 beta strands + 11 alpha helices) with N-terminal domain (residues 1-112, 279-291) and C-terminal domain (residues 113-278), similar to bacterial QPRTases (PDB: 1x1o), active site at alpha/beta open sandwich structure that faces an alpha/beta barrel of the adjacent subunit harbouring the quinolinic acid binding site (Arg102, Arg138, Arg161, Lys139, Lys171, pocket at the centre of the barrel), space group P2(1)2(1)2(1), unit-cell parameters: a = 111.5 A, b = 179.5 A, c = 194.7 A, 12 monomers in asymmetric unit arranged as 2 hexamers of D3 symmetry, sitting-drop vapour diffusion: 5 days, 20°C, 2 microlitre protein solution (10 mg/ml, pH7.5) + 2 microlitre precipitant (0.6 M potassium/sodium tartrate, 0.1 M sodium HEPES pH7.6), resolution of 2 A, phase determination using multiple wavelength anomalous diffraction on crystals of the Se-Met variant |
| 2.4.2.19 | purified recombinant enzyme, hanging drop vapour diffusion method, 10 mg/ml protein, crystallization solution contains 10% PEG 6000, and 0.1 M MES, pH 6.0, X-ray diffraction structure determination and analysis at 2.5 A resolution, molecular replacement, model construction |
