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 amidohy drolases has been crystallized using the vapour-diffusion method and PEG 40 00 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 me ningosepticum as the search model. The asymmetric unit contains four protei n chains composed into a dimer of alpha beta heterodimers, where the subuni ts alpha and beta are the product of autoproteolytic cleavage of the immatu re protein.