Conflicting results exist regarding whether the folding of mammalian ubiquitin at 25 degrees C is a simple, two-state kinetic process or a more complex, three-state process with a defined kinetic intermediate. We have measured folding rate constants up to about 1000 s(-1) using conventional rapid mixing methods in single-jump, double-jump, and continuous-flow modes. The linear dependence of folding rates on denaturant concentration and the lack of an unaccounted "burst-phase" change for the fluorescence signal indicate that a two-state folding model is adequate to describe the folding pathway. This behavior also is seen for folding in the presence of the stabilizing additives 0.23 M sodium sulfate and 1 M sodium chloride. These results stress the need for caution in interpreting deviations from ideal two-state "chevron" behavior when folding is heterogeneous or folding rate constants are near the detection limit. Study holds ProTherm entries: 8624, 8625, 8626, 8627, 8628 Extra Details: folding rate constants; burst-phase; two-state folding model;,folding pathway; chevron
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:36 p.m.
|Number of data points||10|
|Assays/Quantities/Protocols||Experimental Assay: m pH:4.5, ionic:NaCl: 1.0 M ; Experimental Assay: dG_H2O pH:4.5, ionic:NaCl: 1.0 M ; Experimental Assay: m pH:4.5, temp:15.0 C, ionic:NaCl: 1.0 M ; Experimental Assay: dG_H2O pH:4.5, temp:15.0 C, ionic:NaCl: 1.0 M ; Experimental Assay: m pH:4.5, temp:5.0 C, ionic:NaCl: 1.0 M ; Experimental Assay: dG_H2O pH:4.5, temp:5.0 C, ionic:NaCl: 1.0 M ; Experimental Assay: m pH:5.0, ionic:: ; Experimental Assay: dG_H2O pH:5.0, ionic::|
|Libraries||Mutations for sequence MQIFVKTLTGKTITLEVEPSDTIENVKAKIQDKEGIPPDQQRLIFAGKQLEDGRTLSDYNIQKESTLHLVLRLRGG|