A pressure-jump apparatus was employed in investigating the kinetics of protein unfolding and refolding. In the reaction cell, the pressure can be increased or decreased by 100-160 bar within 50-100 microseconds and then held constant. Thus, unfolding and refolding reactions in the time range from 70 microseconds to 70 s can be followed with this technique. Measurements are possible in the transition regions of thermally or denaturant-induced folding in a wide range of temperatures and solvent conditions. We used this pressure-jump method to determine the temperature dependence of the rate constants of unfolding and refolding of the cold shock protein of Bacillus subtilis and of three variants thereof with Phe --> Ala substitutions in the central beta-sheet region. For all variants, the change in heat capacity occurred in refolding between the unfolded and activated states, suggesting that the overall native-like character of the activated state of folding was not changed by the deletion of individual Phe side chains. The Phe27Ala mutation affected the rate of unfolding only; the Phe15Ala and Phe17Ala mutations changed the kinetics of both unfolding and refolding. Although the activated state of folding of the cold shock protein is overall native-like, individual side chains are still in a non-native environment. Study holds ProTherm entries: 16335, 16336, 16337, 16338, 16339, 16340, 16341, 16342, 16343, 16344, 16345, 16346 Extra Details: Thermodynamic parameters for unfolding (Native to Unfolding) cold shock protein, unfolding and refolding kinetics, pressure-jump technique
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:47 p.m.
|Number of data points||45|
|Proteins||Cold shock protein CspB ; Cold shock protein CspB|
|Assays/Quantities/Protocols||Experimental Assay: dCp ; Experimental Assay: dHvH ; Experimental Assay: dG ; Derived Quantity: ddG|
|Libraries||Mutations for sequence MLEGKVKWFNSEKGFGFIEVEGQDDVFVHFSAIQGEGFKTLEEGQAVSFEIVEGNRGPQAANVTKEA|