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Showing 1 to 20 of 37 for “"topoisomerase I"”.
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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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Aktivitätsregulierung der humanen DNS-Topoisomerase I durch den RNS-Spleißfaktor PSF/p54nrb
Experimentelle Stimulierung der humanen DNS-Topoisomerase I durch den Spleißfaktor PSF/p54nrb. Hierbei wurde aus A431-Zellextrakten ein Trimer aus Topoisomerase I und zwei weiteren Proteinen koisoliert. Nach Identifizierung der zwei weiteren Proteine als Spleißfaktor PSF und dessen kleinerem …
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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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Role of topoisomerase I in the stability of the ribosomal DNA of Saccharomyces cerevisiae
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 1998.
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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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Heavy metal toxicity in human lung fibroblasts and inhibition of human topoisomerase-I as a potential mechanism
… of heavy metals inside the body. The enzyme Topoisomerase-I acts on the DNA topological stability and previous works have shown inhibitory effects on the enzyme, can affect DNA sustainability. In this project, the toxicity of cadmium, lead, copper and zinc on human lung fibroblasts at …
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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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DNA supercoiling with a twist
… regulating or conserving DNA torsion. Topoisomerases regulate DNA supercoiling, which has been argued to provide a coherent explanation for the main modes of transcriptional control - stringent control, growth-rate control and growth-phase control during the normal cell growth. In this …
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Untersuchungen zur Interaktion zwischen einer adenoviral-vermittelten Gentherapie und einer Chemotherapie mit Topotecan in etablierten humanen Ovarialkarzinom-Zelllinien
… mit Adenoviren hemmte die Aktivität der Topoisomerase I in <br>NIH:OVCAR3-Zellen und in PEO 4-Zellen. Da die Wirkung von Topotecan direkt proportional zur Aktivität der Topoisomerase I war, ging die reduzierte Topoisomerase I-Aktivität auch mit einer reduzierten Sensitivität gegenüber …
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DNA-Stabilität und Thioredoxin/Thioredoxin Reduktase im Zellkern
… Assays gelang es nachzuweisen, dass Topoisomerase I mit TrxR eine Protein-Protein-Wechsekwirkung eingeht. In einem Rekonstruktionssystem mit rekombinanter Topoisomerase I und gerenigter TrxR ergab sich jedoch keiner Hinweis für eine funktionelle Interaktion in DNA-Relaxations-Assay. …
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Using a chemical genetics approach to dissect the nitrogen signalling pathway in Arabidopsis
… pathway. Camptothecin is known to target topoisomerase I, an enzyme that is increasingly being linked to a role in chromatin re-modelling, in addition to its more familiar roles in DNA replication and repair. The possible epigenetic role of topoisomerase I in repression of NRT2.1 and other …
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Synthesis and anticancer evaluation of novel, functionalised bisindolylmaleimides and indolocarbazoles
… protein kinase inhibition or interference of topoisomerase I activity. This project focuses on exploring the gaps in knowledge surrounding the BIM and ICZ scaffolds by exploring the target’s horizontal and vertical binding space through structural modifications. This was achieved through the …
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Genes with internal repeats require the THO complex for transcription
… transcription is suppressed by overexpression of topoisomerase I, suggesting that the THO complex functions to rectify aberrant structures that arise during transcription.
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The role of DNA supercoiling in the coordinated regulation of gene expression in Helicobacter pylori
… also regulated in H. pylori by overexpression of Topoisomerase I, as detected by genome-wide analysis (DNA microarray). The DNA-bending protein HU is thought to be responsible for influencing the negative supercoiling of DNA, through its ability to wrap DNA. HU is encoded by the hup single gene in …
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Search for new types of deoxyribozymes and development of human topoisomerases inhibitors on the basis of oligonucleotides
… are on the search and development of human topoisomerase I/II inhibitors on the basis of oligonucleotides. Certain non-supercoiled DNA sequences with DNA imperfections such as gap or mismatch next to the topoisomerases cleavage site are designed. Our studies demonstrated some of our newly …
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Anti-breast cancer activity of Coptidis Rhizoma-Euodiae Fructus formulae
… alkaloids. Cell cycle analysis along with topoisomerase I relaxation assay and topoisomerase II decatanation assay were operated to understand the anti-cancer mechanisms of them. Anti-proliferative activity of Zuo Jin pill (Coptis : Euodia = 6 : 1) against both MDA-MB-231 and MCF-7 human …
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Functional Roles of Nucleases in DNA Metabolism and Genome Stability
… for ribonucleotide removal from the genome by Topoisomerase I. In S. cerevisiae, deletion of rnh201, the catalytic subunit of RNase H2, results in the persistence of ribonucleotides remain in the genome, which leads to ~100-fold increase in the frequency of 2-5 bp deletions at di-nucleotide …
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A role for the Bacillus subtilis Structural Maintenance of Chromosomes (BsSMC) protein in chromosome organization and compaction
… in the cell. Conversely, depletion of Topoisomerase I, which increases the amount of negative supercoiling of the chromosome, partially suppresses the phenotype of an smc null mutant. These data are consistent with the model that BsSMC affects chromosome compaction by constraining …
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Type IA topoisomerases: a phylogenomic and biochemical analysis of Methanosarcina acetivorans C2A TopoIII
… protein, eventually renamed to Escherichia coli Topoisomerase I (EcoTopoI), by Prof. James C Wang opened the door to the previously unknown world of molecular machines that manipulate DNA topology. Since then, topoisomerases have been demonstrated to be vital instruments of the cellular machinery …
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