Stimulation of vaccinia topoisomerase I by nucleoside triphosphates.
The rate of relaxation of supercoiled DNA by purified vaccinia topoisomerase I is stimulated 20-fold by 5 mM ATP. A similar effect is elicited by GTP, CTP, UTP, dATP, and adenosine 5'-(beta, gamma-imido)triphosphate. ATP-mediated rate enhancement requires salt as a coactivator. ADP and inorganic pyrophosphate also stimulate relaxation 10-20-fold, whereas AMP and inorganic phosphate have little effect. A model for allosteric activation of topoisomerase by nucleotides is suggested.
Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10021.
J
J
Sekiguchi
S
S
Shuman
D001665:Binding Sites; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004278:DNA, Superhelical / Q000737:chemistry / Q000378:metabolism; D004789:Enzyme Activation; D007700:Kinetics; D008274:Magnesium; D009711:Nucleotides / Q000494:pharmacology*; D012492:Salts; D014616:Vaccinia virus / Q000201:enzymology*
D004278:DNA, Superhelical; D009711:Nucleotides; D012492:Salts; D004264:DNA Topoisomerases, Type I; D008274:Magnesium