Two-step purification of tryptophan-accepting tRNA from Bacillus stearothermophilus☆
Abstract Tryptophan-accepting tRNA has been purified essentially to homogeneity from Bacillus stearothermophilus . Crude tRNA was chromatographed first on benzoylated DEAE-cellulose and then on Sepharose 4B with reverse salt gradient elution. The product has tryptophan acceptor activity in excess of 2 nmol [ 14 C]tryptophan per A 260 unit. This procedure avoids costly aminoacylation, a step characteristic of other one- and two-step procedures. In two separate purifications 7 and 11 mg of tRNA trp were prepared from 750 and 1000 g of frozen cells, respectively. This yield compares favorably with that from other procedures. The pure tRNA trp has been crystallized under several different conditions.