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.
Ali
J A
JA
Department of Biochemistry, University of Leicester, U.K.
Jackson
A P
AP
Howells
A J
AJ
Maxwell
A
A
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