Conformational stability of the Escherichia coli HPr protein: test of the linear extrapolation method and a thermodynamic characterization of cold denaturation.


Abstract

The conformational stability of the histidine-containing phosphocarrier protein (HPr) from Escherichia coli has been determined using a combination of thermal unfolding and urea denaturation experiments. The analysis of the denaturation data provides a measure of the changes in conformational free energy, enthalpy, entropy, and heat capacity that accompany the equilibrium folding of HPr over a wide range of temperature and urea concentrations. In moderate concentrations of urea, HPr undergoes both high- and low-temperature unfolding, allowing for a reliable determination of the change in heat capacity for the conformational transition. The data are consistent with the linear free energy relationship commonly employed to analyze protein denaturation data, even over a relatively large temperature and urea concentration range. Furthermore, we find that a temperature-independent delta Cp is adequate to describe HPr stability over the accessible temperature range. Finally, our data allow us to evaluate the energetics of the urea-protein interaction. For HPr, the changes in excess enthalpy and entropy of the denaturant-protein interaction(s) make only minor contributions to the observed delta H and delta S terms, presumably due in some part to the small size of the HPr protein. Study holds ProTherm entries: 4829, 4830, 4831, 4832, 4833, 4834, 4835, 4836, 4837, 4838, 4839 Extra Details: HPr protein; conformational free energy; size;,temperature-independent delta Cp

Submission Details

ID: ZyNazAXE

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:27 p.m.

Version: 1

Publication Details
Nicholson EM;Scholtz JM,Biochemistry (1996) Conformational stability of the Escherichia coli HPr protein: test of the linear extrapolation method and a thermodynamic characterization of cold denaturation. PMID:8784192
Additional Information

Number of data points 33
Proteins Phosphocarrier protein HPr ; Phosphocarrier protein HPr
Unique complexes 1
Assays/Quantities/Protocols Experimental Assay: Cm temp:50.0 C ; Experimental Assay: m temp:50.0 C ; Experimental Assay: dG_H2O temp:50.0 C ; Experimental Assay: Cm temp:45.0 C ; Experimental Assay: m temp:45.0 C ; Experimental Assay: dG_H2O temp:45.0 C ; Experimental Assay: Cm temp:40.0 C ; Experimental Assay: m temp:40.0 C ; Experimental Assay: dG_H2O temp:40.0 C ; Experimental Assay: Cm temp:35.0 C ; Experimental Assay: m temp:35.0 C ; Experimental Assay: dG_H2O temp:35.0 C ; Experimental Assay: Cm temp:30.0 C ; Experimental Assay: m temp:30.0 C ; Experimental Assay: dG_H2O temp:30.0 C ; Experimental Assay: Cm temp:25.0 C ; Experimental Assay: m temp:25.0 C ; Experimental Assay: dG_H2O temp:25.0 C ; Experimental Assay: Cm temp:20.0 C ; Experimental Assay: m temp:20.0 C ; Experimental Assay: dG_H2O temp:20.0 C ; Experimental Assay: Cm temp:15.0 C ; Experimental Assay: m temp:15.0 C ; Experimental Assay: dG_H2O temp:15.0 C ; Experimental Assay: Cm temp:10.0 C ; Experimental Assay: m temp:10.0 C ; Experimental Assay: dG_H2O temp:10.0 C ; Experimental Assay: Cm temp:5.0 C ; Experimental Assay: m temp:5.0 C ; Experimental Assay: dG_H2O temp:5.0 C ; Experimental Assay: Cm temp:0.0 C ; Experimental Assay: m temp:0.0 C ; Experimental Assay: dG_H2O temp:0.0 C
Libraries Mutations for sequence MFQQEVTITAPNGLHTRPAAQFVKEAKGFTSEITVTSNGKSASAKSLFKLQTLGLTQGTVVTISAEGEDEQKAVEHLVKLMAELE
Sequence Assay Result Units