The equilibrium unfolding reaction of Arc repressor, a dimeric DNA binding protein encoded by bacteriophage P22, can be monitored by fluorescence or circular dichroism changes. The stability of Arc is concentration dependent, and the unfolding reaction is well described as a two-state transition from folded dimer to unfolded monomer. The stability of the protein is decreased at low pH and increased by high salt concentration. The salt dependence suggests that two ions bind preferentially to the folded protein. In 10 mM potassium phosphate (pH 7.3) and 100 mM KCl, the unfolding free energy reaches a maximum near room temperature. The results suggest that at the low protein concentrations where operator DNA binding is normally measured, Arc is predominantly monomeric and unfolded. Study holds ProTherm entries: 3935, 3936, 3937 Extra Details: DNA binding protein; concentration dependent;,two-state transition; low protein concentrations
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:23 p.m.
|Number of data points||9|
|Proteins||Transcriptional repressor arc ; Transcriptional repressor arc|
|Assays/Quantities/Protocols||Experimental Assay: dCp ; Experimental Assay: m ; Experimental Assay: Tm ; Experimental Assay: dHvH ; Experimental Assay: dG ; Experimental Assay: m pH:7.5, temp:20.0 C, buffers:Tris-HCl: 50 mM ; Experimental Assay: dG_H2O pH:7.5, temp:20.0 C, buffers:Tris-HCl: 50 mM ; Experimental Assay: m temp:25.0 C ; Experimental Assay: dG_H2O buffers:Potassium phosphate: 10 mM, temp:25.0 C, pH:7.3|
|Libraries||Mutations for sequence MKGMSKMPQFNLRWPREVLDLVRKVAEENGRSVNSEIYQRVMESFKKEGRIGA|