title: The mechanism of type IA topoisomerases.
abstract: The topology of cellular DNA is carefully controlled by enzymes called topoisomerases. By using single-molecule techniques, we monitored the activity of two type IA topoisomerases in real time under conditions in which single relaxation events were detected. The strict one-at-a-time removal of supercoils we observed establishes that these enzymes use an enzyme-bridged strand-passage mechanism that is well suited to their physiological roles and demonstrates a mechanistic unity with type II topoisomerases.
authors.affiliation: Laboratoire de Physique Statistique et Département de Biologie, Ecole Normale Supérieure, Unité Mixte de Recherche 8550 Centre National de la Recherche Scientifique, 24 Rue Lhomond, 75231 Paris, France. Nynke.Dekker@lps.ens.fr
authors.forename: N H
authors.initials: NH
authors.lastname: Dekker
authors.forename: V V
authors.initials: VV
authors.lastname: Rybenkov
authors.forename: M
authors.initials: M
authors.lastname: Duguet
authors.forename: N J
authors.initials: NJ
authors.lastname: Crisona
authors.forename: N R
authors.initials: NR
authors.lastname: Cozzarelli
authors.forename: D
authors.initials: D
authors.lastname: Bensimon
authors.forename: V
authors.initials: V
authors.lastname: Croquette
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D004264:DNA Topoisomerases, Type I / Q000737:chemistry* / Q000378:metabolism*; D004278:DNA, Superhelical / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D007700:Kinetics; D008954:Models, Biological; D009690:Nucleic Acid Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020124:Thermotoga maritima / Q000201:enzymology / Q000235:genetics
chemical_list: D004278:DNA, Superhelical; D011994:Recombinant Proteins; D004264:DNA Topoisomerases, Type I