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

ABSTRACT: We have performed single-molecule studies of GFP-LacI repressor proteins bound to bacteriophage lambda 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 be 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.

SUBMITTER: Wang YM

PROVIDER: S-EPMC1168954 | biostudies-literature | 2005 Jul

REPOSITORIES: biostudies-literature

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

Wang Y M YM Tegenfeldt Jonas O JO Reisner W W Riehn R R Guan Xiao-Juan XJ Guo Ling L Golding Ido I Cox Edward C EC Sturm James J Austin Robert H RH

Proceedings of the National Academy of Sciences of the United States of America 20050630 28

We have performed single-molecule studies of GFP-LacI repressor proteins bound to bacteriophage lambda 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 be 13, which constitutes only 2.5% of the available sites. This low occupancy level suggests that the repress ...[more]

PMID: 15994229

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