Abstract
The tryptophan synthase genes, trpA and trpB, of Bacillus stearothermophilus IFO13737 were cloned by transformation of tryptophan auxotrophic mutations of the trp genes into Escherichia coli. The genes are located in the order of trpB and trpA, according to their coding orientation, in a 2.5 kb EcoRV-HindIII DNA fragment. The complete nucleotide sequence of this DNA was determined. The trpA and trpB genes consist of 810bp (269 amino acid residues) and 1215bp (404 amino acid residues), respectively. The 5'-proximal portion of the trpB gene was found to overlap 20 nucleotides of the upstream coding region of the trpA gene. The homology of the amino acid sequences of the trp gene products of trpA and trpB of B. stearothermophilus is 35 and 50%, respectively, to those of E. coli, and 55 and 70%, respectively, to those of B. subtilis.
