The 43-kilodalton N-terminal fragment of the DNA gyrase B protein hydrolyzes ATP and binds coumarin drugs.
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.
Department of Biochemistry, University of Leicester, U.K.
J A
JA
Ali
A P
AP
Jackson
A J
AJ
Howells
A
A
Maxwell
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D003001:Cloning, Molecular; D003374:Coumarins / Q000378:metabolism*; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D046911:Macromolecular Substances; D008433:Mathematics; D008962:Models, Theoretical; D008970:Molecular Weight; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism
D003374:Coumarins; D046911:Macromolecular Substances; D010446:Peptide Fragments; D011994:Recombinant Proteins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D004250:DNA Topoisomerases, Type II