15
views
0
recommends
+1 Recommend
0 collections
    8
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      The mechanism of negative DNA supercoiling: a cascade of DNA-induced conformational changes prepares gyrase for strand passage.

      DNA Repair
      Bacteria, classification, enzymology, genetics, metabolism, Binding Sites, DNA Gyrase, chemistry, DNA Topoisomerase IV, DNA, Bacterial, DNA, Superhelical, Models, Molecular, Nucleic Acid Conformation, Protein Conformation, Protein Structure, Tertiary

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          DNA topoisomerases inter-convert different DNA topoisomers in the cell. They catalyze the introduction or relaxation of DNA supercoils, as well as catenation and decatenation. Members of the type I topoisomerase family cleave a single strand of their double-stranded DNA substrate, whereas enzymes of the type II family cleave both DNA strands. Bacterial DNA gyrase, a type II topoisomerase, catalyzes the introduction of negative supercoils into DNA in an ATP-dependent reaction. Gyrase is not present in humans, and constitutes an attractive drug target for the treatment of bacterial and parasite infections. DNA supercoiling by gyrase is believed to occur by a strand passage mechanism, in which one segment of the double-stranded DNA substrate is passed through a (transient) break in a second segment. This mechanism requires the coordinated opening and closing of three protein interfaces, so-called gates, to ensure the directionality of strand passage toward negative supercoiling. Single molecule fluorescence resonance energy transfer experiments are ideally suited to investigate conformational changes during the catalytic cycle of DNA topoisomerases. In this review, we summarize the current knowledge on the cascade of DNA- and nucleotide-induced conformational changes in gyrase that lead to strand passage and negative supercoiling of DNA. We discuss how these conformational changes couple ATP hydrolysis to DNA supercoiling in gyrase, and how the common mechanistic principle of coordinated gate opening and closing is modulated to allow for the catalysis of different reactions by different type II topoisomerases. Copyright © 2014 Elsevier B.V. All rights reserved.

          Related collections

          Author and article information

          Comments

          Comment on this article