Urea denaturation of the lambda repressor has been studied by fluorescence and circular dichroic spectroscopies. Three phases of denaturation could be detected which we have assigned to part of the C-terminal domain, N-terminal domain and subunit dissociation coupled with further denaturation of the rest of the C-terminal domain at increasing urea concentrations. Acrylamide quenching suggests that at least one of the three tryptophan residues of the lambda repressor is in a different environment and its emission maximum is considerably blue-shifted. The transition in low urea concentration (midpoint approximately 2 M) affects the environment of this tryptophan residue, which is located in the C-terminal domain. Removal of the hinge and the N-terminal domain shifts this transition towards even lower urea concentrations, indicating the presence of interaction between hinge on N-terminal and C-terminal domains in the intact repressor. Study holds ProTherm entries: 7163, 7164 Extra Details: three phases of denaturation; subunit dissociation;,acrylamide quenching; intact repressor
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:33 p.m.
|Number of data points||2|
|Proteins||Repressor protein cI ; Repressor protein cI|
|Assays/Quantities/Protocols||Experimental Assay: dG_H2O|
|Libraries||Mutations for sequence STKKKPLTQEQLEDARRLKAIYEKKKNELGLSQESVADKMGMGQSGVGALFNGINALNAYNAALLAKILKVSVEEFSPSIAREIYEMYEAVS|