Identification of a unique domain essential for Escherichia coli DNA topoisomerase III-catalysed decatenation of replication intermediates.
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.
Li
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Department of Pharmaceutical Sciences, University of Maryland, Baltimore School of Pharmacy, 20 North Pine Street, Baltimore, MD 21201, USA.
Mondragón
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Hiasa
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Marians
K J
KJ
DiGate
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RJ
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
D004269:DNA, Bacterial; D004278:DNA, Superhelical; D011993:Recombinant Fusion Proteins; D004264:DNA Topoisomerases, Type I