Molecular cloning of gyrA and gyrB genes of Mycobacterium tuberculosis: analysis of nucleotide sequence.

We have recently reported the cloning of gyrA and gyrB genes from Mycobacterium tuberculosis H37Ra [Curr. Science, (1994) 66, 664-667]. Here, we present the complete nucleotide sequence of gyrB gene from M. tuberculosis H37Ra along with the flanking regions. The gyrA gene has been located 34 nucleotides downstream of gyrB and has been partially sequenced; both the genes seem to be transcribed from the promoter elements located upstream of gyrB coding sequence. The gyrB gene encodes a polypeptide of 714 amino acids. The deduced amino acid sequences of gyrB and a part of gyrA show extensive homology to the corresponding genes from other bacterial species. The DNA gyrase of M. tuberculosis could be utilised to develop new line of antitubercular drugs.