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. Hydroxychloroquine monitoring eyes Malaria chemoprophylaxis chloroquine phosphate tablet 500 mg in the news Can i bleach my hair taking plaquenil for lupus Typically plasmid DNA molecules are used to measure DNA supercoiling status inside bacterial cells. In this chapter, we describe how to isolate plasmid DNA molecules from E. coli cells and determine DNA supercoiling density by 1% agarose gel electrophoresis containing chloroquine using plasmid pACYC184 as an example. Circular DNA increases as the molecules become su- percoiled in the positive sense. At chloroquine con- centrations on either side of the mobility minimum, individual species of supercoiled DNA differing by one superhelical turn are resolved. In these gels, plasmid 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. 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 DNA Topology Fundamentals - Tufts University, MIT Escherichia coli DNA Topoisomerase I Mutants Increased. Plaquenil and hyperpigmentation sjogren'sChloroquine cancer Key words Chloroquine; DNA; Intercalator; Plasmodium; Malaria; Antimalarial Introduction The mechanism of action of chloroquine has not yet been clearly elucidated. Chloroquine has been found to have several actions that could be re- sponsible for its antimalarial activity intercala- tion into DNA 1, alkalinization of parasite ly- sosomes 2, and binding to hemin 3. Binding of chloroquine to DNA - ScienceDirect. Time-resolved chloroquine-induced relaxation of.. Interaction of chloroquine with linear and supercoiled.. Because a DNA-protein activity can lead to either an overwinding or an underwinding of the helix, supercoiling can occur in either direction. Determining whether a plasmid contains positively or negatively supercoiled DNA is possible, thanks to an agarose gel containing an intercalating agent known to positively supercoil DNA, such as chloroquine. Purified DNA was analyzed in 2D chloroquine gels to reveal the supercoiling distribution of the monomer plasmids. A cartoon representation of how the plasmid distribution relates to supercoiling. 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.