Single-molecule studies of repressor-DNA interactions show long-range interactions

Y. M. Wang, Jonas O. Tegenfeldt, W. Reisner, R. Riehn, Xiao Juan Guan, Ling Guo, Ido Golding, Edward C. Cox, James Sturm, Robert H. Austin

Research output: Contribution to journalArticlepeer-review


We have performed single-molecule studies of GFP-Lacl repressor proteins bound to bacteriophage λ DNA containing a 256 tandem lac operator insertion confined in nanochannels. An integrated photon molecular counting method was developed to determine the number of proteins bound to DNA. By using this method, we determined the saturated mean occupancy of the 256 tandem lac operators to the 13, which constitutes only 2.5% of the available sites. This low occupancy level suggests that the repressors influence each other even when they are widely separated, at distances on the order of 200 nm, or several DNA persistence lengths.

Original languageEnglish (US)
Pages (from-to)9796-9801
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number28
StatePublished - Jul 12 2005
Externally publishedYes


  • Binding coefficient
  • Multiple sites
  • Transcription factors

ASJC Scopus subject areas

  • General


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