Crystallization and preliminary X-ray crystallographic analysis of the tRNA-specific adenosine deaminase fromStreptococcus pyogenes

Abstract

The tRNA-specific adenosine deaminase from the pathogenic bacteria Streptococcus pyogenes (spTAD) has been overexpressed in Escherichia coli and crystallized in the presence of Zn 2+ ion at 295 K using ammonium sulfate as a precipitant. Flash-cooled crystals of spTAD diffracted to 2.0 Å using 30%(v/v) glycerol as a cryoprotectant. X-ray diffraction data have been collected to 2.0 Å 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 Å . The asymmetric unit contains one subunit of spTAD, with a corresponding crystal volume per protein weight (V M ) of 3.3 Å 3 Da À1 and a solvent content of 62.7%.

Crystal structure of the tRNA‐specific adenosine deaminase from Streptococcus pyogenes

“…The cloning, purification, and crystallization of TadA from Streptococcus pyogenes has been reported 12. Briefly, His‐tagged TadA in pET22b vector was expressed in an Escherichia coli strain BL21 (DE3).…”