Crystallization and preliminary crystallographic studies of a new L-asparaginase encoded by the Escherichia coli genome

A new Escherichia coli L-asparaginase belonging to the class of Ntn amidohydrolases has been crystallized using the vapour-diffusion method and PEG 4000 as the precipitant. The crystals belong to the orthorhombic space group P2(1)2(1)2(1) (unit-cell parameters a = 50.3, b = 77.6, c = 148.2 Angstrom) and diffract to 1.65 Angstrom resolution. The structure has been solved by molecular replacement using aspartylglucosaminidase from Flavobacterium meningosepticum as the search model. The asymmetric unit contains four protein chains composed into a dimer of alpha beta heterodimers, where the subunits alpha and beta are the product of autoproteolytic cleavage of the immature protein.