title: Identification of a unique domain essential for Escherichia coli DNA topoisomerase III-catalysed decatenation of replication intermediates.
abstract: A 17-amino-acid residue domain has been identified in Escherichia coli DNA topoisomerase III (Topo III) that is essential for Topo III-mediated resolution of DNA replication intermediates in vitro. Deletion of this domain reduced Topo III-catalysed resolution of DNA replication intermediates and decatenation of multiply linked plasmid DNA dimers by four orders of magnitude, whereas reducing Topo III-catalysed relaxation of negatively supercoiled DNA substrates only 20-fold. The presence of this domain has been detected in multiple plasmid-encoded topoisomerases, raising the possibility that these enzymes may also be decatenases.
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland, Baltimore School of Pharmacy, 20 North Pine Street, Baltimore, MD 21201, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Li
authors.forename: A
authors.initials: A
authors.lastname: Mondragón
authors.forename: H
authors.initials: H
authors.lastname: Hiasa
authors.forename: K J
authors.initials: KJ
authors.lastname: Marians
authors.forename: R J
authors.initials: RJ
authors.lastname: DiGate
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D004261:DNA Replication; D004264:DNA Topoisomerases, Type I / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004278:DNA, Superhelical / Q000737:chemistry / Q000378:metabolism; D019281:Dimerization; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D004269:DNA, Bacterial; D004278:DNA, Superhelical; D011993:Recombinant Fusion Proteins; D004264:DNA Topoisomerases, Type I