Journal article
Guanidine Hydrochloride Unfolding of Peptide Helices: Separation of Denaturant and Salt Effects
Biochemistry (Easton), Vol.35(22), pp.7292-7297
06/04/1996
DOI: 10.1021/bi960341i
PMID: 8679559
Abstract
To provide a model for understanding the unfolding of proteins by the chemical denaturant guanidine hydrochloride, we have measured helix unfolding for homologous series of peptides with the repeating sequence Ala-Glu-Ala- Ala-Lys-Ala and chain lengths from 7 to 50 residues. The free energy for helix unfolding varies as a function of guanidinium chloride (GdmCl) for all the peptides. The slope of the linear plot of the free energy of helix formation as a function of the molar concentration of GdmCl, termed the m- value, was found to be strongly dependent on the total ionic strength of the solution. A comparison of the m-value for urea denaturation of the same series of peptides [Scholtz, J. M., Barrick, D., York, E. J., Stewart, J. M., and Baldwin, R. L. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 185-189] reveals that, under many conditions. GdmCl is roughly twice as effective as a denaturant than urea on a molar basis, in agreement with many studies on proteins. However, when the ionic strength of aqueous GdmCl is controlled with additional NaCl, it is possible to separate the observed m-value for GdmCl solutions into two components: one that is identical to that found for urea and a second which depends only on the molar concentration of the chloride anion. Therefore, for these peptides, an equimolar mixture of urea and NaCl is nearly as effective as GdmCl in unfolding the helical conformation.
Details
- Title: Subtitle
- Guanidine Hydrochloride Unfolding of Peptide Helices: Separation of Denaturant and Salt Effects
- Creators
- Jeni S. Smith - Texas A&M UniversityJ. Martin Scholtz - Texas A&M University
- Resource Type
- Journal article
- Publication Details
- Biochemistry (Easton), Vol.35(22), pp.7292-7297
- Publisher
- American Chemical Society
- DOI
- 10.1021/bi960341i
- PMID
- 8679559
- ISSN
- 0006-2960
- eISSN
- 1520-4995
- Language
- English
- Date published
- 06/04/1996
- Academic Unit
- Research Administration; Pharmaceutical Sciences and Experimental Therapeutics; Biochemistry and Molecular Biology; Chemistry
- Record Identifier
- 9984293082102771
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