Overexpression, purification, crystallization and preliminary X-ray crystallographic studies of a proline-specific aminopeptidase from Aneurinibacillus sp. strain AM-1.

To elucidate the structure and molecular mechanism of a characteristic proline-specific aminopeptidase produced by the thermophile Aneurinibacillus sp. strain AM-1, its gene was cloned and the recombinant protein was overexpressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. X-ray diffraction data were collected to 1.8 A resolution from the recombinant aminopeptidase crystal. The crystals belong to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 93.62, b = 68.20, c = 76.84 A. A complete data set was also obtained from crystals of SeMet-substituted aminopeptidase. Data in the resolution range 20-2.1 A from the MAD data set from the SeMet-substituted crystal were used for phase determination.