Nucleotide sequence and molecular characterization of the DNA gyrase genes from Clostridium acetobutylicum

The DNA gyrase genes from Clostridium acetobutylicum were cloned using a PCR-based approach. The nucleotide sequence of a 5805-bp region has been determined which contains part of recF, an open reading frame with unknown function (orfX), and the complete gyrB and gyrA genes. The gyrB and gyrA genes encode proteins of 637 and 829 amino acid residues, respectively, which show significant homology to gyrase sequences from several eubacteria. Residues thought to be important to structure and function of the subunits are conserved, but some differences in amino acid residues believed to be involved in the binding of gyrase antagonists, such as quinolone and coumarin drugs, have been observed. No putative promoter regions could be detected upstream of gyrB and gyrA, and evidence for a cotranscription of recF, orfX, and gyrB was obtained by reverse transcriptase PCR experiments. (C) 1996 Academic Press.