| Eukaryotic topoisomerase II. Characterization of enzyme turnover. | |
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MedLine Citation:
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PMID: 3015913 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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While the binding of adenyl-5'-yl imidodiphosphate (App(NH)p) to Drosophila melanogaster topoisomerase II induces a double-stranded DNA passage reaction, its nonhydrolyzable beta,gamma-imidodiphosphate bond prevents enzyme turnover (Osheroff, N., Shelton, E. R., and Brutlag, D. L. (1983) J. Biol. Chem. 258, 9536-9543). Therefore, this ATP analog was used to characterize the interactions between Drosophila topoisomerase II and DNA which occur after DNA strand passage but before enzyme turnover. In the presence of App(NH)p, a stable post-strand passage topoisomerase II-nucleic acid complex is formed when circular DNA substrates are employed. Although noncovalent in nature, these complexes are resistant to increases in ionic strength and show less than 5% dissociation under salt concentrations (greater than 500 mM) that disrupt 95% of the enzyme-DNA interactions formed in the absence of App(NH)p or under a variety of other conditions that do not support DNA strand passage. These results strongly suggest that the process of enzyme turnover not only regenerates the active conformation of topoisomerase II but also confers upon the enzyme the ability to disengage from its nucleic acid product. Experiments with linear DNA molecules indicate that after strand passage has taken place, topoisomerase II may be able to travel along its DNA substrate by a linear diffusion process that is independent of enzyme turnover. Further studies demonstrate that the regeneration of the enzyme's catalytic center does not require enzyme turnover, since topoisomerase II can cleave double-stranded DNA substrates after strand passage has taken place. Finally, while the 2'-OH and 3'-OH of ATP are important for its interaction with Drosophila topoisomerase II, neither are required for turnover. |
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Authors:
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N Osheroff |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The Journal of biological chemistry Volume: 261 ISSN: 0021-9258 ISO Abbreviation: J. Biol. Chem. Publication Date: 1986 Jul |
Date Detail:
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Created Date: 1986-09-17 Completed Date: 1986-09-17 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 2985121R Medline TA: J Biol Chem Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 9944-50 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adenosine Diphosphate
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metabolism Adenylyl Imidodiphosphate / metabolism Animals Cytidine Triphosphate / metabolism DNA Topoisomerases, Type II / metabolism* DNA, Circular / metabolism DNA, Superhelical / metabolism Drosophila melanogaster / enzymology* Electrophoresis, Agar Gel Kinetics Magnesium / metabolism Magnesium Chloride Sodium Dodecyl Sulfate / pharmacology |
| Grant Support | |
ID/Acronym/Agency:
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GM-33944/GM/NIGMS NIH HHS; RR-05424/RR/NCRR NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/DNA, Circular; 0/DNA, Superhelical; 151-21-3/Sodium Dodecyl Sulfate; 25612-73-1/Adenylyl Imidodiphosphate; 58-64-0/Adenosine Diphosphate; 65-47-4/Cytidine Triphosphate; 7439-95-4/Magnesium; 7786-30-3/Magnesium Chloride; EC 5.99.1.3/DNA Topoisomerases, Type II |
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