Thermodynamics of the thermal unfolding of eglin c in the presence and absence of guanidinium chloride.


Abstract

The thermal unfolding of eglin c, a small proteinase inhibitor of molecular weight 8.1 kDa, is studied by means of high sensitivity scanning calorimetry over a wide pH range in dilute buffer solutions, and in the presence of varying concentrations of guanidinium chloride at pH 7.00 and 10.55. The temperature of half-completion of the unfolding transition, t1/2, in dilute buffer varies from 41 degrees C at pH 1.1 to 86 degrees C at pH 7.0 to 10.55, with corresponding enthalpy changes of approximately 40 kcal mol-1 and 71 kcal mol-1. This latter enthalpy change, amounting to 8.7 cal g-1, is unusually large for a protein, especially for one of unusually small molecular weight. Addition of 3.3 M guanidinium chloride at pH 10.55 lowered t1/2 from 86 degrees C to 40 degrees C and decreased the enthalpy change from approximately 71 kcal mol-1 to 25 kcal mol-1. Study holds ProTherm entries: 9898, 9899, 9900, 9901, 9902, 9903, 9904, 9905, 9906, 9907, 9908, 9909, 9910, 9911, 9912, 9913, 9914, 9915, 9916, 9917, 9918 Extra Details: thermodynamics; thermal unfolding; eglin c; guanidinium chloride

Submission Details

ID: W4up4FzT4

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:39 p.m.

Version: 1

Publication Details
Bae SJ;Sturtevant JM,Biophys. Chem. (1995) Thermodynamics of the thermal unfolding of eglin c in the presence and absence of guanidinium chloride. PMID:7626743
Additional Information

Number of data points 63
Proteins Chymotrypsinogen A ; Eglin C
Unique complexes 1
Assays/Quantities/Protocols Experimental Assay: dCp buffers:glycine: 50mM, pH:10.55 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:10.55 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:10.55 ; Experimental Assay: dCp buffers:glycine: 50mM, pH:10.5 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:10.5 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:10.5 ; Experimental Assay: dCp buffers:glycine: 50mM, pH:10.05 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:10.05 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:10.05 ; Experimental Assay: dCp pH:9.2, buffers:bicine: 50mM ; Experimental Assay: dHcal pH:9.2, buffers:bicine: 50mM ; Experimental Assay: Tm pH:9.2, buffers:bicine: 50mM ; Experimental Assay: dCp buffers:Sodium phosphate: 50mM, pH:8.0 ; Experimental Assay: dHcal buffers:Sodium phosphate: 50mM, pH:8.0 ; Experimental Assay: Tm buffers:Sodium phosphate: 50mM, pH:8.0 ; Experimental Assay: dCp buffers:Sodium phosphate: 50mM, pH:7.05 ; Experimental Assay: dHcal buffers:Sodium phosphate: 50mM, pH:7.05 ; Experimental Assay: Tm buffers:Sodium phosphate: 50mM, pH:7.05 ; Experimental Assay: dCp pH:7.01, buffers:Sodium phosphate: 50mM ; Experimental Assay: dHcal pH:7.01, buffers:Sodium phosphate: 50mM ; Experimental Assay: Tm pH:7.01, buffers:Sodium phosphate: 50mM ; Experimental Assay: dCp buffers:Sodium phosphate: 50mM, pH:7.0 ; Experimental Assay: dHcal buffers:Sodium phosphate: 50mM, pH:7.0 ; Experimental Assay: Tm buffers:Sodium phosphate: 50mM, pH:7.0 ; Experimental Assay: dCp buffers:glycine: 50mM, pH:3.25 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:3.25 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:3.25 ; Experimental Assay: dCp buffers:glycine: 50mM, pH:3.0 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:3.0 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:3.0 ; Experimental Assay: dCp buffers:glycine: 50mM, pH:2.93 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:2.93 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:2.93 ; Experimental Assay: dCp buffers:glycine: 50mM, pH:2.85 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:2.85 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:2.85 ; Experimental Assay: dCp buffers:glycine: 50mM, pH:2.75 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:2.75 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:2.75 ; Experimental Assay: dCp buffers:glycine: 50mM, pH:2.5 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:2.5 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:2.5 ; Experimental Assay: dCp buffers:glycine: 50mM, pH:2.25 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:2.25 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:2.25 ; Experimental Assay: dCp buffers:glycine: 50mM, pH:2.15 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:2.15 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:2.15 ; Experimental Assay: dCp buffers:glycine: 50mM, pH:2.0 ; Experimental Assay: dHcal buffers:glycine: 50mM, pH:2.0 ; Experimental Assay: Tm buffers:glycine: 50mM, pH:2.0 ; Experimental Assay: dCp pH:1.8, buffers:glycine-HCl: 50mM ; Experimental Assay: dHcal pH:1.8, buffers:glycine-HCl: 50mM ; Experimental Assay: Tm pH:1.8, buffers:glycine-HCl: 50mM ; Experimental Assay: dCp buffers:glycine-HCl: 50mM, pH:1.65 ; Experimental Assay: dHcal buffers:glycine-HCl: 50mM, pH:1.65 ; Experimental Assay: Tm buffers:glycine-HCl: 50mM, pH:1.65 ; Experimental Assay: dCp pH:1.3, buffers:glycine-HCl: 50mM ; Experimental Assay: dHcal pH:1.3, buffers:glycine-HCl: 50mM ; Experimental Assay: Tm pH:1.3, buffers:glycine-HCl: 50mM ; Experimental Assay: dCp pH:1.1, buffers:glycine-HCl: 50mM ; Experimental Assay: dHcal pH:1.1, buffers:glycine-HCl: 50mM ; Experimental Assay: Tm pH:1.1, buffers:glycine-HCl: 50mM
Libraries Mutations for sequence E:CGVPAIQPVLSGLSRIVNGEEAVPGSWPWQVSLQDKTGFHFCGGSLINENWVVTAAHCGVTTSDVVVAGEFDQGSSSEKIQKLKIAKVFKNSKYNSLTINNDITLLKLSTAASFSQTVSAVCLPSASDDFAAGTTCVTTGWGLTRYTNANTPDRLQQASLPLLSNTNCKKYWGTKIKDAMICAGASGVSSCMGDSGGPLVCKKNGAWTLVGIVSWGSSTCSTSTPGVYARVTALVNWVQQTLAAN/I:TEFGSELKSFPEVVGKTVDQAREYFTLHYPQYDVYFLPEGSPVTLDLRYNRVRVFYNPGTNVVNHVPHVG
Sequence Assay Result Units