Isolation of Escherichia coli precursor tRNAs containing modified nucleoside Q.

Affinity chromatography based on the complex formation of the modified nucleoside Q with boronic acid has been applied to the isolation of specific tRNA precursors containing this modified nucleoside. When [32P]RNA isolated from an Escherichia coli strain containing a thermolabile ribonuclease P was chromatographed on dihydroxyboryl-substituted cellulose, the precursors for asparagine, aspartate, histidine, and tyrosine tRNA were specifically retained. All precursors were monomeric. The nucleotide sequences of four asparagine tRNA precursors were determined.