The 43-kilodalton N-terminal fragment of the DNA gyrase B protein hydrolyzes ATP and binds coumarin drugs

Biochemistry. 1993 Mar 16;32(10):2717-24. doi: 10.1021/bi00061a033.


We have cloned and overexpressed a gene encoding a 43-kDa protein corresponding to the N-terminal fragment of the DNA gyrase B subunit. We show that this protein hydrolyzes ATP and binds coumarin drugs. The hydrolysis of ATP shows distinctly non-Michaelis-Menten kinetics and is consistent with a scheme in which the active form of the protein is a dimer, a conclusion supported by molecular weight studies. The coumarin drugs bind very tightly to the 43-kDa fragment, with novobiocin binding to the protein monomer and coumermycin A1 apparently inducing the formation of a dimer. The implications of these results with respect to the mechanism of supercoiling by DNA gyrase and the inhibition of gyrase by coumarin drugs are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / metabolism*
  • Adenosine Triphosphate / metabolism*
  • Cloning, Molecular
  • Coumarins / metabolism*
  • DNA Topoisomerases, Type II / genetics
  • DNA Topoisomerases, Type II / isolation & purification
  • DNA Topoisomerases, Type II / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Escherichia coli / enzymology*
  • Kinetics
  • Macromolecular Substances
  • Mathematics
  • Models, Theoretical
  • Molecular Weight
  • Peptide Fragments / isolation & purification
  • Peptide Fragments / metabolism*
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism


  • Coumarins
  • Macromolecular Substances
  • Peptide Fragments
  • Recombinant Proteins
  • Adenosine Triphosphate
  • Adenosine Triphosphatases
  • DNA Topoisomerases, Type II