Crystallization and preliminary X-ray analysis of the Mj0684 gene product, a putative aspartate aminotransferase, from Methanococcus jannaschii

A putative aspartate aminotransferase from the hyperthermophilic archaeon Methanococcus jannaschii encoded by the Mj0684 gene has been overexpressed in Escherichia coli and crystallized at 296 K using the sitting-drop vapour-diffusion method. The crystals belong to space group P4₁2₁2 (or P4₃2₁2), with unit-cell parameters a = b = 111.87, c = 60.86 Å. They diffract to 2.2 Å resolution using Cu Kα X-rays. The asymmetric unit contains a single subunit of the recombinant Mj0684 gene product, giving a corresponding V_M of 2.25 ų Da^-1 and a solvent content of 45.3% by volume. An X-ray diffraction data set has been collected to 2.2 Å at 295 K.