Perturbed pKA-values in the Denatured States of Proteins

Tan, Yee‐Joo; Oliveberg, Mikael; Davis, Ben; Fersht, Alan R.

doi:10.1006/jmbi.1995.0670

Cited by 148 publications

(223 citation statements)

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“…They also offer a relatively simple method for probing electrostatic interactions in the DSE [1,6,17,[23][24][25][26][27]. The approach exploits the linkage relationship that connects pH dependent changes in ΔG o with the difference in the number of protons bound to the native state and to the DSE [23]: (1) ΔQ in equation 1 is equal to the difference in the number of protons bound to the native state (Q N ) and to the DSE (Q D ) and is a function of pH.…”

Section: Resultsmentioning

confidence: 99%

“…In most of the cases examined there are clear deviations between the observed pH dependence of ΔG o and the behavior predicted based upon a fully unfolded DSE (Table-1). Examples include CI2, barnase, Staphylococcal Nuclease (SNase), the turkey ovomucoid third domain, the N-terminal domain of L9 and a mutant of the B1 domain of protein G [1,17,[24][25][26]28]. Most of these proteins lack disulfides thus the DSE interactions are not simply a consequence of the presence of covalent cross links.…”

Section: Electrostatic Interactions Are Found In the Denatured State mentioning

confidence: 99%

“…Mutations are made and their effect upon the ΔΔG 0 vs. pH curve analyzed. In favorable cases it is even possible to fit the curves to obtain the difference in the native state and DSE pK a of the mutated residue [26]. It is important to note that changes in the native state pK a 's caused by the mutation can be rigorously taken into account by using native state pK a 's values measured for each mutant.…”

Section: Mutational Analysis Of Electrostatic Interactions In the Denmentioning

confidence: 99%

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Electrostatic interactions in the denatured state ensemble: Their effect upon protein folding and protein stability

Cho¹,

Sato²,

Horng³

et al. 2008

Archives of Biochemistry and Biophysics

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It is now recognized that the denatured state ensemble (DSE) of proteins can contain significant amounts of structure, particularly under native conditions. Well-studied examples include small units of hydrogen bonded secondary structure, particularly helices or turns as well hydrophobic clusters. Other types of interactions are less well characterized and it has often been assumed that electrostatic interactions play at most a minor role in the DSE. However, recent studies have shown that both favorable and unfavorable electrostatic interactions can be formed in the DSE. These can include surprisingly specific non-native interactions that can even persist in the transition state for protein folding. DSE electrostatic interactions can be energetically significant and their modulation either by mutation or by varying solution conditions can have a major impact upon protein stability. pH dependent stability studies have shown that electrostatic interactions can contribute up to 4 kcal mol −1 to the stability of the DSE.

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Section: Resultsmentioning

confidence: 99%

Section: Electrostatic Interactions Are Found In the Denatured State mentioning

confidence: 99%

Section: Mutational Analysis Of Electrostatic Interactions In the Denmentioning

confidence: 99%

See 1 more Smart Citation

Electrostatic interactions in the denatured state ensemble: Their effect upon protein folding and protein stability

Cho¹,

Sato²,

Horng³

et al. 2008

Archives of Biochemistry and Biophysics

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“…For these reasons, pK a values obtained directly from the D state are more accurate than those inferred from random coil model compounds 12,28,29,35 . To model the D state of GCN4p we studied the protein in 6 M urea, since this is often the endpoint of protein denaturation studies 13 .…”

Section: Pk a Values In The Denatured Statementioning

confidence: 99%

Electrostatic Contributions to the Stability of the GCN4 Leucine Zipper Structure

Matousek

Ciani

Fitch

et al. 2007

Journal of Molecular Biology

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SummaryIon pairs are ubiquitous in X-ray structures of coiled coils, and mutagenesis of charged residues can result in large stability losses. By contrast, pK a values determined by NMR in solution often predict only small contributions to stability from charge interactions. To help reconcile these results we used triple-resonance NMR to determine pK a values for all groups that ionize between pH 1 and 13 in the 33-residue leucine zipper fragment, GCN4p. In addition to the native state we also determined comprehensive pK a values for two models of the GCN4p denatured state: the protein in 6 M urea, and unfolded peptide fragments of the protein in water. Only residues that form ion pairs in multiple X-ray structures of GCN4p gave large pK a differences between the native and denatured states. Moreover, electrostatic contributions to stability were not equivalent for oppositely charged partners in ion pairs, suggesting that the interactions between a charge and its environment are as important as those within the ion pair. The pH dependence of protein stability calculated from NMR-derived pK a values agreed with the stability profile measured from equilibrium urea-unfolding experiments as a function of pH. The stability profile was also reproduced with structure-based continuum electrostatic calculations, although contributions to stability were overestimated at the extremes of pH. We consider potential sources of errors in the calculations, and how pK a predictions could be improved. Our results show that although hydrophobic packing and hydrogen bonding have dominant roles, electrostatic interactions also make significant contributions to the stability of the coiled coil.

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“…The acidic intermediate state of cyt c was the first example for which the term molten globule was used [2]. Proteins undergoing acid denaturation are unfolded at low pH because of the presence of destabilizing repulsive interactions between like charges in the protein [6,7]. Salts have been known to affect the physicochemical properties of the proteins such as their solubility, stability and pK a to a great extent [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic insights into the binding of ANS with the salt induced molten globule states of cytochrome c

Sharma

Kishore

2009

The Journal of Chemical Thermodynamics

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Perturbed pKA-values in the Denatured States of Proteins

Cited by 148 publications

References 0 publications

Electrostatic interactions in the denatured state ensemble: Their effect upon protein folding and protein stability

Electrostatic interactions in the denatured state ensemble: Their effect upon protein folding and protein stability

Electrostatic Contributions to the Stability of the GCN4 Leucine Zipper Structure

Thermodynamic insights into the binding of ANS with the salt induced molten globule states of cytochrome c

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