A single point mutation in the DNA gyrase A protein greatly reduces binding of fluoroquinolones to the gyrase-DNA complex.

ABSTRACT

Binding of the quinolone drug norfloxacin to gyrase and DNA has been investigated. We have detected binding to gyrase-DNA complex but find no significant binding to either gyrase or DNA alone. Enzyme containing gyrase A protein with the mutation Ser-83 to Trp (conferring quinolone resistance) showed greatly reduced drug binding.