Cloning and complete nucleotide sequence of the Bacillus stearothermophilus tryptophanyl tRNA synthetase gene

The Bacillus stearothermophilus NCA 1503 tryptophanyl tRNA synthetase (WTS; EC 6.1.1.2) gene has been cloned in Escherichia coli and the amino acid (aa) sequence of the enzyme deduced unequivocally from the DNA sequence of the cloned gene. The predicted aa sequence of the WTS enzyme agrees with the previously determined aa sequence except that the DNA sequence indicates a third Arg residue at the C terminus of the enzyme over the two Arg residues indicated by sequencing the protein itself. The trpS gene consists of a 984-bp open reading frame commencing with an ATG start codon and ending with a TAA stop codon. Putative transcriptional promoters, a Shine-Dalgarno sequence and a transcription terminator have been identified. Thus the trpS gene probably constitutes a single transcriptional unit.