Abstract
DNA gyrase from B. subtilis 168 was purified by affinity chromatography on novobiocin-Sepharose and shown to consist of 2 subunits, A and B, with MW of 100,000 and 85,000, respectively. The B subunit, which contains novobiocin-sensitive ATPase activity, could complement the gyrA protein of Escherichia coli. No complementation was detected between the A subunit and the E. coli gyrB protein.