Rapid solid phase isolation of 20 specific tRNAs from Escherichia coli

Abstract

A solid phase procedure has been developed for the rapid isolation of all 20 species of tRNA from Escherichia coli. The overall yields for a single preparation cycle ranged from 62 to 96%, the average being 80%. The values for the amino acid acceptor activities of the tRNA species equaled those reported in the literature for highly purified tRNAs. Starting from crude tRNA, a given tRNA species can easily be isolated in less than 2 h. One milliliter of the resin, which is reusable, is sufficient for the isolation of 200 mg of a specific tRNA. The procedure requires a bifunctional reagent, one moiety of which (--SO2Cl) reacts with the amino acid on the aminoacylated tRNA, the other, with the --SH group on the resin. Thus, only the desired tRNA species is bound to the resin; any of the other tRNAs in the filtrate can be isolated in another cycle. Raising the pH results in deacylation and release from the resin of the desired tRNA species. For tRNA Cys, it is necessary to block the --SH of cysteine prior to reaction with the bifunctional reagent. Side reactions involving the bifunctional reagent. Side reactions involving the bifunctional reagent and tRNA are either easily reversible or negligible (less than 0.01%).