Crystallization and preliminary crystallographic analysis of two eukaryotic fructosyl peptide oxidases.

Fructosyl peptide oxidase (FPOX) catalyses the oxidation of α-glycated dipeptides such as N(α)-(1-deoxy-D-fructos-1-yl)-L-valyl-L-histidine (Fru-ValHis) and is used in the diagnosis of diabetes mellitus. Here, two thermostable mutants of FPOX, CFP-T7 and EFP-T5M, were crystallized by the sitting-drop vapour-diffusion method. The crystal of CFP-T7 belonged to the tetragonal space group P4(1)2(1)2, with unit-cell parameters a = b = 110.09, c = 220.48 Å, and that of EFP-T5M belonged to the monoclinic space group P2(1), with unit-cell parameters a = 43.00, b = 230.05, c = 47.27 Å, β = 116.99°. The crystals of CFP-T7 and EFP-T5M diffracted to 1.8 and 1.6 Å resolution, respectively.