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The peculiar nature of the guanidine hydrochloride-induced two-state denaturation of staphylococcal nuclease: a calorimetric study.
Biochemistry. 1999 Aug 24; 38(34):11216-22.B

Abstract

This work determines the ratio of DeltaH(vH) /DeltaH(cal) for staphylococcal nuclease (SN) denaturation in guanidine hydrochloride (GdnHCl) to test whether GdnHCl-induced denaturation is two-state. Heats of mixing of SN as a function of [GdnHCl] were determined at pH 7.0 and 25 degrees C. The resulting plot of DeltaH(mix) vs [GdnHCl] exhibits a sigmoid shaped curve with linear pre- and post-denaturational base lines. Extending the pre- and post-denaturational lines to zero [GdnHCl] gives a calorimetric DeltaH (DeltaH(cal)) of 24.1 +/- 1.0 kcal/mol, for SN denaturation in the limit of zero GdnHCl concentration. Guanidine hydrochloride-induced denaturation Gibbs energy changes in the limit of zero denaturant concentration (DeltaG degrees (N)(-)(D)) at pH 7. 0 were determined for SN from fluorescence measurements at fixed temperatures over the range from 15 to 35 degrees C. Analysis of the resulting temperature-dependent DeltaG degrees (N)(-)(D) data defines a van't Hoff denaturation enthalpy change (DeltaH(vH)) of 26. 4 +/- 2.8 kcal/mol. The model-dependent van't Hoff DeltaH(vH) divided by the model-independent DeltaH(cal) gives a ratio of 1.1 +/- 0.1 for DeltaH(vH)/DeltaH(cal), a result that rules out the presence of thermodynamically important intermediate states in the GdnHCl-induced denaturation of SN. The likelihood that GdnHCl-induced SN denaturation involves a special type of two-state denaturation, known as a variable two-state process, is discussed in terms of the thermodynamic implications of the process.

Authors+Show Affiliations

Yang M
Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston 77555-1052, USA.
Liu D
No affiliation info available
Bolen DW
No affiliation info available

MeSH

CalorimetryGuanidineHydrogen-Ion ConcentrationMicrococcal NucleaseModels, ChemicalProtein DenaturationSpectrometry, FluorescenceTemperatureThermodynamics

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10460179

Citation

Yang, M, et al. "The Peculiar Nature of the Guanidine Hydrochloride-induced Two-state Denaturation of Staphylococcal Nuclease: a Calorimetric Study." Biochemistry, vol. 38, no. 34, 1999, pp. 11216-22.
Yang M, Liu D, Bolen DW. The peculiar nature of the guanidine hydrochloride-induced two-state denaturation of staphylococcal nuclease: a calorimetric study. Biochemistry. 1999;38(34):11216-22.
Yang, M., Liu, D., & Bolen, D. W. (1999). The peculiar nature of the guanidine hydrochloride-induced two-state denaturation of staphylococcal nuclease: a calorimetric study. Biochemistry, 38(34), 11216-22.
Yang M, Liu D, Bolen DW. The Peculiar Nature of the Guanidine Hydrochloride-induced Two-state Denaturation of Staphylococcal Nuclease: a Calorimetric Study. Biochemistry. 1999 Aug 24;38(34):11216-22. PubMed PMID: 10460179.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The peculiar nature of the guanidine hydrochloride-induced two-state denaturation of staphylococcal nuclease: a calorimetric study. AU - Yang,M, AU - Liu,D, AU - Bolen,D W, PY - 1999/8/25/pubmed PY - 1999/8/25/medline PY - 1999/8/25/entrez SP - 11216 EP - 22 JF - Biochemistry JO - Biochemistry VL - 38 IS - 34 N2 - This work determines the ratio of DeltaH(vH) /DeltaH(cal) for staphylococcal nuclease (SN) denaturation in guanidine hydrochloride (GdnHCl) to test whether GdnHCl-induced denaturation is two-state. Heats of mixing of SN as a function of [GdnHCl] were determined at pH 7.0 and 25 degrees C. The resulting plot of DeltaH(mix) vs [GdnHCl] exhibits a sigmoid shaped curve with linear pre- and post-denaturational base lines. Extending the pre- and post-denaturational lines to zero [GdnHCl] gives a calorimetric DeltaH (DeltaH(cal)) of 24.1 +/- 1.0 kcal/mol, for SN denaturation in the limit of zero GdnHCl concentration. Guanidine hydrochloride-induced denaturation Gibbs energy changes in the limit of zero denaturant concentration (DeltaG degrees (N)(-)(D)) at pH 7. 0 were determined for SN from fluorescence measurements at fixed temperatures over the range from 15 to 35 degrees C. Analysis of the resulting temperature-dependent DeltaG degrees (N)(-)(D) data defines a van't Hoff denaturation enthalpy change (DeltaH(vH)) of 26. 4 +/- 2.8 kcal/mol. The model-dependent van't Hoff DeltaH(vH) divided by the model-independent DeltaH(cal) gives a ratio of 1.1 +/- 0.1 for DeltaH(vH)/DeltaH(cal), a result that rules out the presence of thermodynamically important intermediate states in the GdnHCl-induced denaturation of SN. The likelihood that GdnHCl-induced SN denaturation involves a special type of two-state denaturation, known as a variable two-state process, is discussed in terms of the thermodynamic implications of the process. SN - 0006-2960 UR - https://www.unboundmedicine.com/medline/citation/10460179/The_peculiar_nature_of_the_guanidine_hydrochloride_induced_two_state_denaturation_of_staphylococcal_nuclease:_a_calorimetric_study_ L2 - https://doi.org/10.1021/bi9909400 DB - PRIME DP - Unbound Medicine ER -