Abstract
Recent biochemical and crystallographic results suggest that a type II DNA topoisomerase acts as an ATP-modulated clamp with two sets of jaws at opposite ends: a DNA-bound enzyme can admit a second DNA through one set of jaws; upon binding ATP, this DNA is passed through an enzyme-mediated opening in the first DNA and expelled from the enzyme through the other set of jaws. Experiments based on the introduction of reversible disulfide links across one dimer interface of yeast DNA topoisomerase II have confirmed this mechanism. The second DNA is found to enter the enzyme through the gate formed by the N-terminal parts of the enzyme and leave it through the gate close to the C termini.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adenosine Triphosphate / metabolism
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Adenylyl Imidodiphosphate / pharmacology
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Binding Sites
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Computer Graphics
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Computer Simulation
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Cross-Linking Reagents
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DNA Topoisomerases, Type II / chemistry*
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DNA Topoisomerases, Type II / metabolism*
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DNA, Single-Stranded / chemistry*
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DNA, Single-Stranded / metabolism*
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Macromolecular Substances
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Models, Molecular*
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Nucleic Acid Conformation
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Plasmids
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Point Mutation
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Protein Structure, Secondary*
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Recombinant Proteins / chemistry
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Recombinant Proteins / metabolism
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Saccharomyces cerevisiae / enzymology
Substances
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Cross-Linking Reagents
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DNA, Single-Stranded
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Macromolecular Substances
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Recombinant Proteins
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Adenylyl Imidodiphosphate
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Adenosine Triphosphate
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DNA Topoisomerases, Type II