Crystallization of Bacillus subtilis Tryptophanyl-tRNA Synthetase

Tryptophanyl-tRNA synthetase from Bacillus subtilis was overexpressed in Escherichia coli and was purified using column chromatography on DEAE-Sephacel and hydroxyapatite columns. Single crystals of the synthetase were grown by vapor diffusion at 4°C from pH 5·5 solutions of polyethylene glycol 8000 containing magnesium ATP and l-tryptophan. The crystals diffracted to about 4·0 Å resolution at -150°C and appeared to belong to the orthorhombic space group P 21212 with unit cell dimensions: a =143·6 Å, b=111·6 Å, c =50·6 Å with one dimer in the asymmetric unit.