MF-5168

It has been suggested that 4-quinolones may bind to different sites of the DNA gyrase-DNA complex.To study this and establish which of the quinolone moieties are involved in the different binding sites, an anal. was made of the ability of 4-quinolone derivatives having various substituents in positions 1, 5, 6, 7, and 8 to inhibit DNA replication of Escherichia coli strains.Apparently 2 different sites, located in the A and B subunits, in DNA gyrase are involved in quinolone binding; these sites show differential interaction with quinolone substituents and the mechanistic consequences for bacterial inhibition differ.