| Autor: |
Chen TY; Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA., Santiago AG; Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA., Jung W; Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA., Krzemiński Ł; Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA., Yang F; Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA., Martell DJ; Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA., Helmann JD; Department of Microbiology, Cornell University, Ithaca, New York 14853, USA., Chen P; Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA. |
| Abstrakt: |
Binding and unbinding of transcription regulators at operator sites constitute a primary mechanism for gene regulation. While many cellular factors are known to regulate their binding, little is known on how cells can modulate their unbinding for regulation. Using nanometer-precision single-molecule tracking, we study the unbinding kinetics from DNA of two metal-sensing transcription regulators in living Escherichia coli cells. We find that they show unusual concentration-dependent unbinding kinetics from chromosomal recognition sites in both their apo and holo forms. Unexpectedly, their unbinding kinetics further varies with the extent of chromosome condensation, and more surprisingly, varies in opposite ways for their apo-repressor versus holo-activator forms. These findings suggest likely broadly relevant mechanisms for facile switching between transcription activation and deactivation in vivo and in coordinating transcription regulation of resistance genes with the cell cycle. |
