CLONING AND NUCLEOTIDE-SEQUENCES OF THE TOPOISOMERASE-IV PARC AND PARE GENES OF MYCOPLASMA-HOMINIS

The topoisomerase IV parC and parE genes from the wall-less organism M ycoplasma hominis PG21 were cloned and sequenced. The coupled genes ar e located far from the DNA gyrase genes gyrA and gyrB. They encode pro teins of 639 and 866 amino acids, respectively. As expected, the encod ed ParE and ParC proteins exhibit higher homologies with the topoisome rase IV subunits of the gram-positive bacteria Staphylococcus aureus a nd Streptococcus pneumoniae than with their Escherichia coli counterpa rts. The conserved regions include the Tyr residue of the active site and the region involved in quinolone resistance (quinolone resistance- determining region [QRDR]) in ParC and the ATP-binding site and the QR DR in ParE.