Crystallization and preliminary crystallographic study of asparagine synthetase from Escherichia coli

Crystals of Escherichia coli asparagine synthetase have been obtained from 45% saturated ammonium sulfate solution at pH 7.5 by using its Cys-free (Cys51-->Ala, Cys315-->Ala) mutant. The crystals belong to space group P2(1), with cell dimensions a = 52.90(4), b = 126.2 (2), c = 52.8 (1) A and beta = 105.3(1) degrees. The self-rotation function specifies that there is one dimer in the asymmetric unit and the subunits are related by a non-crystallographic twofold axis. Complete data sets up to 2.7 A resolution have been collected on an R-AXIS IIc imaging-plate system.