Escherichia coli condensin MukB stimulates topoisomerase IV activity by a direct physical interaction

Yinyin Li, Nichole K. Stewart, Anthony J. Berger, Seychelle Vos, Allyn J. Schoeffler, James M. Berger, Brian T. Chait, Martha G. Oakley

Research output: Contribution to journalArticlepeer-review


In contrast to the current state of knowledge in the field of eukaryotic chromosome segregation, relatively little is known about the mechanisms coordinating the appropriate segregation of bacterial chromosomes. In Escherichia coli, the MukB/E/F complex and topoisomerase IV (Topo IV) are both crucial players in this process. Topo IV removes DNA entanglements following the replication of the chromosome, whereas MukB, a member of the structural maintenance of chromosomes protein family, serves as a bacterial condensin. We demonstrate here a direct physical interaction between the dimerization domain of MukB and the C-terminal domain of the ParC subunit of Topo IV. In addition, we find that MukB alters the activity of Topo IV in vitro. Finally, we isolate a MukB mutant, D692A, that is deficient in its interaction with ParC and show that this mutant fails to rescue the temperature-sensitive growth phenotype of a mukB- strain. These results show that MukB and Topo IV are linked physically and functionally and indicate that the activities of these proteins are not limited to chromosome segregation but likely also play a key role in the control of higher-order bacterial chromosome structure.

Original languageEnglish (US)
Pages (from-to)18832-18837
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number44
StatePublished - Nov 2 2010
Externally publishedYes


  • Bacterial chromosome segregation
  • Mass spectrometry

ASJC Scopus subject areas

  • General


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