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The MukB-topoisomerase IV interaction mutually suppresses their catalytic activities.

Authors
  • Kumar, Rupesh1
  • Bahng, Soon1
  • Marians, Kenneth J1
  • 1 Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
Type
Published Article
Journal
Nucleic Acids Research
Publisher
Oxford University Press
Publication Date
Mar 21, 2022
Volume
50
Issue
5
Pages
2621–2634
Identifiers
DOI: 10.1093/nar/gkab1027
PMID: 34747485
Source
Medline
Language
English
License
Unknown

Abstract

The bacterial condensin MukB and the cellular chromosomal decatenase, topoisomerase IV interact and this interaction is required for proper condensation and topological ordering of the chromosome. Here, we show that Topo IV stimulates MukB DNA condensation by stabilizing loops in DNA: MukB alone can condense nicked plasmid DNA into a protein-DNA complex that has greater electrophoretic mobility than that of the DNA alone, but both MukB and Topo IV are required for a similar condensation of a linear DNA representing long stretches of the chromosome. Remarkably, we show that rather than MukB stimulating the decatenase activity of Topo IV, as has been argued previously, in stoichiometric complexes of the two enzymes each inhibits the activity of the other: the ParC subunit of Topo IV inhibits the MukF-stimulated ATPase activity of MukB and MukB inhibits both DNA crossover trapping and DNA cleavage by Topo IV. These observations suggest that when in complex on the DNA, Topo IV inhibits the motor function of MukB and the two proteins provide a stable scaffold for chromosomal DNA condensation. © The Author(s) 2021. Published by Oxford University Press on behalf of Nucleic Acids Research.

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