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Showing 1 to 17 of 17 for “"DNA topoisomerase"”.
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Mechanistic Characterization of the Mitochondrial Type I DNA Topoisomerase and a Study of Genes Containing Type I DNA Topoisomerase-Related Domains
<p>The mitochondrial type I DNA topoisomerase (mt-topo I) serves an important function in the mitochondrion by relaxing mtDNA supercoils to allow for replication of the mitochondrial genome as well as for gene expression. The mt-topo I's role in essential processes, such as replication and …
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Enzyme Architecture and Flexibility Affect DNA Topoisomerase I Function
<p>DNA topoisomerase I (Top1) is a highly conserved enzyme composed of four domains: a positively charged N-terminus; a DNA binding/core domain that circumscribes duplex DNA; a non-conserved linker domain; and a C-terminal/catalytic domain. Top1 catalyzes changes in DNA topology by transient …
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CDC45 Function Alters Cell Sensitivity to DNA Topoisomerase I Poisons
<p>Eukaryotic DNA topoisomerase I (Top1) is a highly conserved enzyme that functions to manage the torsional strain of DNA during cellular processes such as transcription, replication, chromatid condensation and recombination. The enzyme binds duplex DNA and through a series of strand cleavage and …
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Genome Instability Associated with DNA Topoisomerase Activity during Gene Transcription
Las lesiones que se producen en el ADN suponen un desafío continuo para la integridad genómica, siendo las roturas de doble cadena del ADN (DSBs) la lesión más citotóxica para la célula. Numerosos estudios han mostrado recientemente que una fuente fisiológica de DSBs es la actividad de las …
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The physiological role of the two isoforms of DNA topoisomerase II in human cells
Unique functions of DNA topoisomerase IIalpha and IIbeta have been suggested. A human cell line which carries a homozygeous mutation of the nuclear localization sequence of the topoisomerase IIalpha gene expresses the isoform outside the nucleus at the onset of mitosis. At mitosis topoisomerase …
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Investigation of the Substrate Recognition Characteristics and Kinetics of Mammalian Mitochondrial DNA Topoisomerase I
<p>Topoisomerases are DNA-modifying enzymes found in prokaryotes, eukaryotes, viruses and organelles such as chloroplast and mitochondria. Information about these enzymes in eukaryotic systems is mostly limited to nuclear enzymes, although our laboratory has been characterizing the biochemical and …
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Age-Associated Hepatic Drug Transporter Expression and Its Implications for Pediatric Pharmacotherapyflexibility affect DNA topoisomerase I function
<p>Members of the ATP-binding cassette (ABC) family of drug transporter proteins translocate various endogenous and exogenous substrates across intra- and extracellular membranes. Two specific ABC transporters, the multidrug resistance 1/P-glycoprotein (MDR1/P-gp) and the multidrug resistance …
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Studies on Type I and Type II DNA Topoisomerases From Mammalian Mitochondria
<p>Mammalian mitochondria contain a unique DNA topoisomerase I with characteristics of both nuclear and bacterial type I DNA topoisomerases. This enzyme, purified from bovine liver, requires cations as cofactors and possesses optimal activity at pH 7.0, 37°C and either 150 mM K+ or Na+ ions. …
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Aktive DNS-Topoisomerase II Alpha ist eine Komponente des salzresistenten zentrosomalen Strukturgerüstes
… berichteten wir, daß der monoklonale, für die DNA-topoisomerase IIalpha spezifische Antikörper Ki-S1 nicht nur die Kerne menschlicher A431-Zellen, sondern auch extranucleäre Strukturen färbt (Meyer et. al., 1997, J. Cell. Biol. 136, 775). Diese Strukturen waren wahrscheinlich Zentrosomen. In …
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Electrophoretic Mobilities of Topoisomers of ΦX174 DNA
… demonstrated the existence of several circular DNA forms that appear in cells infected with the bacteriophage ΦX174.</p> <p>Wt/<em>am</em>3 heteroduplex molecules containing a single base mismatch (relaxed RFI molecules) were constructed <em>in vitro</em>, purified by sedimentation, and analyzed …
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Staphylococcus aureus DNA gyrase: mechanism and drug targeting
… the development of antibiotic resistance. DNA gyrase is an essential bacterial type II DNA topoisomerase that manipulates DNA topology by performing transient double-strand breaks and DNA strand passage. As gyrase is vital for bacterial survival, it is an effective antibacterial target. By …
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Characterization, Interaction and Chemoprevention of Potent Constituents From Grape Cell Culture
… cell culture extract and subfractions on human DNA topoisomerase II for cancer chemoprevention; (2) to characterize constituents in the most potent fractions; (3) to investigate interactions between bioactive polyphenols present in the most potent fractions; and finally (4) to assess …
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A Mutated Peptide Database for the Analysis of Proteomic Mass Spectrometry Data
… among others. Mutations in the oncogene KRAS, DNA Topoisomerase 1 (TOP1), and TGF-beta receptor type 2 (TGFBR2) represent only a small sample of the mutations that were detected. Overall, the XMAn v3 database proved to be very useful in enabling the identification and characterization of …
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Molecular Characterization of Fluoroquinolone Resistance in Streptococcus pneumoniae
… resistance determining regions (QRDRs) of DNA gyrase and/or DNA topoisomerase IV, and (2) drug efflux via unknown transporter proteins. Although previous studies have examined the selection of these resistance mechanisms to varying degrees, a more rigorous and extensive investigation was …
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The role of topoisomerase II in amsacrine resistance
… including acridines, have been shown to induce topoisomerase II-associated DNA breaks both in cultured mammalian cells and in vitro in the presence of purified mammalian DNA topoisomerase II. However, mechanisms linking these protein-associated DNA breaks with drug cytotoxicity are poorly …
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Linker Histone Medicated Regulation of Mitotic Chromosome Compaction and Individualization
… Recent studies have shown how condensins and DNA topoisomerase II organize the mitotic chromosome. However, the regulation of these factors in maintaining proper chromosome size in different cell types remains a mystery. Here, I investigated the role of the linker histone variant H1.8 in …