Supercoiling is important in a number of biological processes, such as compacting DNA, and by regulating access to the genetic code, DNA supercoiling strongly affects DNA metabolism and possibly gene expression. Additionally, certain enzymes such as topoisomerases are able to change DNA topology to facilitate functions such as DNA replication or transcription. Chloroquine and proguanil anti malaria tablets Treatment of rheumatoid arthritis with methotrexate and hydroxychloroquine Atthese chloroquine con- centrations, all plasmids are negatively supercoiled; those migrating more rapidly are more highly supercoiled and, therefore, have lower linking numbers. Jul 16, 2011 In our study, we used an intercalating drug, chloroquine, which is known to decrease the twist of the double helix and thus altered the conformation of the whole DNA. During our experiments, a chloroquine solution was added while imaging a few highly condensed plasmid nanoparticles in solution. Because chloroquine induces positive supercoiling, at this low concentration, the negatively supercoiled DNA should relax and run more slowly than negatively supercoiled DNA more chloroquine will. Adding or subtracting twists, as some enzymes can do, imposes strain. In a "relaxed" double-helical segment of B-DNA, the two strands twist around the helical axis once every 10.4–10.5 base pairs of sequence. Chloroquine dna supercoiling Supercoiling in prokaryotic and eukaryotic DNA changes in., Time-resolved chloroquine-induced relaxation of supercoiled. Chloroquine tablet 500mg Jul 09, 2002 In the presence of the DNA intercalator chloroquine 5 μg/ml, this DNA was largely relaxed and migrated during agarose gel electrophoresis as if it contained a few − supercoils Fig. 2 A, lane 8. Incubation of pRLM375 DNA with DNA gyrase alone for 10 min introduced about 5 or 6 additional − supercoils Fig. 2 A, lane 7. Potent stimulation of transcription-coupled DNA supercoiling.. Using an agarose gel with chloroquine to study the DNA.. DNA Supercoiling Measurement in Bacteria.. Interaction of chloroquine with linear and supercoiled DNAs. Effect on the torsional dynamics, rigidity, and twist energy parameter The type IIA subfamily of topoisomerases both resolves DNA entanglements and regulates DNA supercoiling through a strand passage mechanism whereby one DNA duplex, the transfer T segment, is transported through a double-stranded break in a second DNA, the gate G segment 4,7. As the global supercoiling state of the chlamydial plasmid changed more than twofold between 24 and 46 hpi, we isolated the native plasmid at additional time points during the developmental cycle to determine the temporal pattern of DNA supercoiling in Chlamydia. We electrophoresed the plasmids on agarose gels at different chloroquine concentrations to best resolve the topoisomer bands.