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Molecular basis for the effect of urea and guanidinium chloride on the dynamics of unfolded polypeptide chains

Title data

Möglich, Andreas ; Krieger, Florian ; Kiefhaber, Thomas:
Molecular basis for the effect of urea and guanidinium chloride on the dynamics of unfolded polypeptide chains.
In: Journal of Molecular Biology. Vol. 345 (7 January 2005) Issue 1 . - pp. 153-162.
ISSN 0022-2836
DOI: https://doi.org/10.1016/j.jmb.2004.10.036

Abstract in another language

Chemical denaturants are frequently used to unfold proteins and to characterize mechanisms and transition states of protein folding reactions. The molecular basis of the effect of urea and guanidinium chloride (GdmCl) on polypeptide chains is still not well understood. Models for denaturant--protein interaction include both direct binding and indirect changes in solvent properties. Here we report studies on the effect of urea and GdmCl on the rate constants (k(c)) of end-to-end diffusion in unstructured poly(glycine-serine) chains of different length. Urea and GdmCl both lead to a linear decrease of lnk(c) with denaturant concentration, as observed for the rate constants for protein folding. This suggests that the effect of denaturants on chain dynamics significantly contributes to the denaturant-dependence of folding rate constants for small proteins. We show that this linear dependency is the result of two additive non-linear effects, namely increased solvent viscosity and denaturant binding. The contribution from denaturant binding can be quantitatively described by Schellman's weak binding model with binding constants (K) of 0.62(+/-0.01)M(-1) for GdmCl and 0.26(+/-0.01)M(-1) for urea. In our model peptides the number of binding sites and the effect of a bound denaturant molecule on chain dynamics is identical for urea and GdmCl. The results further identify the polypeptide backbone as the major denaturant binding site and give an upper limit of a few nanoseconds for residence times of denaturant molecules on the polypeptide chain.

Further data

Item Type: Article in a journal
Refereed: Yes
Additional notes: PubMed-ID: 15567418
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Biochemistry > Chair Biochemistry - Univ.-Prof. Dr. Andreas Möglich
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Professorship Biochemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Biochemistry
Result of work at the UBT: No
DDC Subjects: 500 Science > 540 Chemistry
Date Deposited: 20 May 2015 07:41
Last Modified: 20 May 2015 07:41
URI: https://eref.uni-bayreuth.de/id/eprint/13616