Crystallization and X ray diffraction data analyses of the enzyme urocanate hydratase from trypanosoma cruzi

Abstract

Trypanosoma cruzi is the only trypanosomatid pathogenic to humans in which the four enzymes of the histidine degradation pathway were found up to now. The enzyme urocanate hydratase from Trypanosoma cruzi catalyzes the second step of histidine degradation and is essential for the catabolic conversion of urocanate to 4-imidazolone-5-propionate, which finally yields glutamate and further glutmaine and tricarboxylic acid cycle intermediates such as α-ketoglutarate. The recombinant Cterminally His6-tagged protein was expressed in Escherichia coli, purified in a homogenous form and crystallized in several conditions, with the best crystals obtained with 0.04 M dipotassium hydrogen phosphate, 16.00 % (w/v) polyethylene glycol 8,000 and 22.00 % (v/v) glycerol. X ray diffraction data were collected to 2.61 Å resolution. The crystals belong to the monoclinic space group P21, with unit cell parameters a = 85.12, b = 137.63, c = 117.69 Å, β = 94.69 ° and are suitable for molecular replacement phasing. The asymmetric unit contains four monomers, with a VM of 2.3 Å3/Da and a solvent content of 45.9 %.