Dna Topoisomerases Type Ii
Mostrando 13-24 de 74 artigos, teses e dissertações.
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13. Eukaryotic topoisomerases recognize nucleic acid topology by preferentially interacting with DNA crossovers.
Eukaryotic topoisomerases recognize DNA topology and preferentially react with positively or negatively supercoiled molecules over relaxed substrates. To elucidate the mechanism of this recognition, we examined the interaction of topoisomerases with DNA by electron microscopy. Under all conditions employed, approximately 90% of the bound type I or II enzyme
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14. DNA topoisomerases from rat liver: physiological variations.
Besides the nicking-closing (topoisomerase I) activity, an ATP-dependent DNA topoisomerase is present in rat liver nuclei. The enzyme, partially purified, is able to catenate in vitro closed DNA circles in a magnesium-dependent, ATP-dependent, histone H1-dependent reaction, and to decatenate in vitro kinetoplast DNA networks to yield free minicircles in a ma
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15. Toprim--a conserved catalytic domain in type IA and II topoisomerases, DnaG-type primases, OLD family nucleases and RecR proteins.
Iterative profile searches and structural modeling show that bacterial DnaG-type primases, small primase-like proteins from bacteria and archaea, type IA and type II topoisomerases, bacterial and archaeal nucleases of the OLD family and bacterial DNA repair proteins of the RecR/M family contain a common domain, designated Toprim (topoisomerase-primase) domai
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16. Importance of the Fourth Alpha-Helix within the CAP Homology Domain of Type II Topoisomerase for DNA Cleavage Site Recognition and Quinolone Action
We report that point mutations causing alteration of the fourth alpha-helix (α4-helix) of the CAP homology domain of eukaryotic (Saccharomyces cerevisiae) type II topoisomerases (Ser740Trp, Gln743Pro, and Thr744Pro) change the selection of type II topoisomerase-mediated DNA cleavage sites promoted by Ca2+ or produced by etoposide, the fluoroquinolone CP-115
American Society for Microbiology.
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17. Forces on chromosomal DNA during anaphase.
In the course of anaphase, the chromosomal DNA is submitted to the traction of the spindle. Several physical problems are associated with this action. In particular, the sister chromatids are generally topologically intertwined at the onset of anaphase, and the removal of the intertwinings results from a coupling between the enzymatic action of type II DNA t
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18. Similarity in the catalysis of DNA breakage and rejoining by type IA and IIA DNA topoisomerases
Studies of yeast DNA topoisomerase II with various alanine-substitution mutations provide strong biochemical support of a recent hypothesis that the type IA and IIA DNA topoisomerases act similarly in their cleavage and rejoining of DNA. DNA breakage and rejoining by either a type IA or a type IIA enzyme are shown to involve cooperation between a DNA-binding
The National Academy of Sciences.
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19. A Mutation in Escherichia coli DNA Gyrase Conferring Quinolone Resistance Results in Sensitivity to Drugs Targeting Eukaryotic Topoisomerase II
Fluoroquinolones are broad-spectrum antimicrobial agents that target type II topoisomerases. Many fluoroquinolones are highly specific for bacterial type II topoisomerases and act against both DNA gyrase and topoisomerase IV. In Escherichia coli, mutations causing quinolone resistance are often found in the gene that encodes the A subunit of DNA gyrase. One
American Society for Microbiology.
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20. Structure of the topoisomerase VI-B subunit: implications for type II topoisomerase mechanism and evolution
Type IIA and type IIB topoisomerases each possess the ability to pass one DNA duplex through another in an ATP-dependent manner. The role of ATP in the strand passage reaction is poorly understood, particularly for the type IIB (topoisomerase VI) family. We have solved the structure of the ATP-binding subunit of topoisomerase VI (topoVI-B) in two states
Oxford University Press.
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21. Role for topoisomerases in the release of DNA into the detergent-soluble fraction of eukaryotic cells.
Detergent-soluble DNA is the fraction (2-4%) of DNA that is released into the supernate upon mild detergent lysis. It is nonmitochondrial in origin. It labels efficiently with deoxy[3H]ribonucleosides and the labeling is prevented by inhibitors of polymerase alpha and ribonucleotide reductase. In previous publications we have characterized detergent-soluble
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22. Single-molecule study of DNA unlinking by eukaryotic and prokaryotic type-II topoisomerases
Type-II topoisomerases are responsible for untangling DNA during replication by removing supercoiled and interlinked DNA structures. Using a single-molecule micromanipulation setup, we follow the real-time decatenation of two mechanically braided DNA molecules by Drosophila melanogaster topoisomerase (Topo) II and Escherichia coli Topo IV. Although Topo
National Academy of Sciences.
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23. Anaphase chromatid motion: involvement of type II DNA topoisomerases.
Sister chromatids are topologically intertwined at the onset of anaphase: their segregation during anaphase is known to require strand-passing activity by type II DNA topoisomerase. We propose that the removal of the intertwinings involves at the same time the traction of the mitotic spindle and the activity of topoisomerases. This implies that the velocity
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24. Topoisomerase function during replication-independent chromatin assembly in yeast.
DNA topoisomerases I and II are the two major nuclear enzymes capable of relieving torsional strain in DNA. Of these enzymes, topoisomerase I plays the dominant role in relieving torsional strain during chromatin assembly in cell extracts from oocytes, eggs, and early embryos. We tested if the topoisomerases are used differentially during chromatin assembly