Crystallization and preliminary crystallographic analysis of yeast cytosine deaminase.

Cytosine deaminase is an attractive candidate for anticancer gene therapy through its catalysis of the deamination of the prodrug 5-fluorocytosine to 5-fluorouracil. Recombinant yeast cytosine deaminase has been crystallized with the inhibitor 2-hydroxypyrimidine in 10% 2-propanol, 20% polyethylene glycol 4000, 0.1 M HEPES pH 7.5. The crystals belong to space group P2(1), with unit-cell parameters a = 45.31, b = 53.33, c = 64.29 A, beta = 99.98 degrees and one dimer per asymmetric unit. The crystals diffract X-rays beyond 1.5 A resolution and an initial atomic model has been built based on selenomethionyl multiwavelength anomalous data at 2 A resolution.