Interlocking of plasmid DNAs due to lac repressor-operator interaction

Hai Young Wu, Kawai Lau, Leroy F. Liu

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


The presence of a single lac repressor binding sequence on plasmid DNAs is shown to mediate the formation of interlocked dimers in E. coli. The presence of both homo- and hetero-interlocked dimers suggests that the lac repressor complex can bring together randomly two plasmid DNA molecules to facilitate gyrase-mediated interlocking. The exclusive formation of multiply intertwined dimers also suggests that the lac repressor complex may bind simultaneously to a pair of replicated daughter plasmid molecules prior to their segregation. The formation of interlocked plasmid DNAs can be indicative of interaction between two DNA bound proteins in vivo.

Original languageEnglish
Pages (from-to)1104-1114
Number of pages11
JournalJournal of Molecular Biology
Issue number4
Publication statusPublished - Dec 20 1992
Externally publishedYes


  • DNA looping
  • DNA replicating intermediate
  • catenation
  • lac operator
  • lac repressor

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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