Crystallization and preliminary X-ray crystallographic analysis of the tRNA-specific adenosine deaminase from Streptococcus pyogenes.

The tRNA-specific adenosine deaminase from the pathogenic bacteria Streptococcus pyogenes (spTAD) has been overexpressed in Escherichia coli and crystallized in the presence of Zn2+ ion at 295 K using ammonium sulfate as a precipitant. Flash-cooled crystals of spTAD diffracted to 2.0 A using 30%(v/v) glycerol as a cryoprotectant. X-ray diffraction data have been collected to 2.0 A using synchrotron radiation. The crystal belongs to the tetragonal space group P4(2)2(1)2, with unit-cell parameters a = b = 81.042, c = 81.270 A. The asymmetric unit contains one subunit of spTAD, with a corresponding crystal volume per protein weight (VM) of 3.3 A3 Da(-1) and a solvent content of 62.7%.