Cloning of yeast lysyl- and phenylalanyl-tRNA synthetase genes

Cloning of yeast lysyl- and phenylalanyl-tRNA synthetase genes was accomplished by probing a lambda gt11 recombinant DNA expression library with antibodies directed against the purified enzymes. Several DNA clones encoding either the alpha or the beta subunit of phenylalanyl-tRNA synthetase were isolated. In each case, the inserted DNA was oriented in the same direction with respect to the lambda gt11 lacZ transcription unit, giving rise to the expression of hybrid proteins. The corresponding DNA fragments constitute suitable hybridization probes for the isolation of complete nucleotide sequences encoding the alpha and beta subunits of the enzyme. Recombinant DNA lambda gt11 clones encoding lysyl-tRNA synthetase were also selected. One of these contained yeast DNA inserted with the opposite orientation with respect to lacZ. The lysogen corresponding to that recombinant DNA phage produced an active, native lysyl-tRNA synthetase. The 3.6 kbp DNA insert contained all the information necessary for the expression of yeast lysyl-tRNA synthetase in E. coli.