A Two-State Model of Hydrophobic Hydration That Produces Compensating Enthalpy and Entropy Changes

Lee, B.; Graziano, Giuseppe

doi:10.1021/ja9538389

Cited by 191 publications

(164 citation statements)

References 35 publications

(53 reference statements)

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“…Enthalpy/entropy compensation phenomena are well known for quite different processes of biopolymers [45,51,63,[66][67][68][69] and have been discussed on the basis of various models [64,65,[70][71][72][73][74]. Such a compensation also refers to the present case of cytochrome c unfolding as shown in Fig.…”

Section: Thermodynamics Of the Interfacial Redox Processmentioning

confidence: 99%

The impact of urea-induced unfolding on the redox process of immobilised cytochrome c

et al. 2010

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We have studied the effect of urea-induced unfolding on the electron transfer process of yeast iso-1-cytochrome c and its mutant K72AK73AK79A adsorbed on electrodes coated by mixed 11-mercapto-1-undecanoic acid/ 11-mercapto-1-undecanol self-assembled monolayers. Electrochemical measurements, complemented by surface enhanced resonance Raman studies, indicate two distinct states of the adsorbed proteins that mainly differ with respect to the ligation pattern of the haem. The native state, in which the haem is axially coordinated by Met80 and His18, displays a reduction potential that slightly shifts to negative values with increasing urea concentration. At urea concentrations higher than 6 M, a second state prevails in which the Met80 ligand is replaced by an additional histidine residue. This structural change in the haem pocket is associated with an approximately 0.4 V shift of the reduction potential to negative values. These two states were found for both the wild-type protein and the mutant in which lysine residues 72, 73 and 79 had been substituted by alanines. The analysis of the reduction potentials, the reaction enthalpies and entropies as well as the rate constants indicates that these three lysine residues have an important effect on stabilising the protein structure in the adsorbed state and facilitating the electron transfer dynamics.

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Section: Thermodynamics Of the Interfacial Redox Processmentioning

confidence: 99%

The impact of urea-induced unfolding on the redox process of immobilised cytochrome c

et al. 2010

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“…Each state is assigned thermodynamic parameters based on experimental data. There are several such related models (for example, [26][27][28] and recent refinements. 29-31 These models fairly reproduce the observed positive ΔC P for hydration of nonpolar surfaces as well as the temperature dependence of that ΔC P , but they appear to do so despite an incorrect description of the ΔH and ΔS of nonpolar solute hydration.…”

Section: Two-state Thermodynamic Modelsmentioning

confidence: 99%

Heat capacity changes associated with nucleic acid folding

2006

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Whereas heat capacity changes (ΔC P s) associated with folding transitions are commonplace in the literature of protein folding, they have long been considered a minor energetic contributor in nucleic acid folding. Recent advances in the understanding of nucleic acid folding and improved technology for measuring the energetics of folding transitions have allowed a greater experimental window for measuring these effects. We present in this review a survey of current literature that confronts the issue of ΔC P s associated with nucleic acid folding transitions. This work helps to gather the molecular insights that can be gleaned from analysis of ΔC P s and points toward the challenges that will need to be overcome if the energetic contribution of ΔC P terms are to be put to use in improving free energy calculations for nucleic acid structure prediction.

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“…In order to obtain this behavior from our model we must have temperature dependent ǫ w and ∆s w . We use the four level Muller, Lee, and Graziano (MLG) model of water [21,22,1] to obtain ǫ w (kT ) and ∆s w (kT ). In this model water molecules can be either in disordered (broken hydrogen bonds) or ordered states.…”

Section: Closed Loop Phase Diagrammentioning

confidence: 99%

Role of solvent for globular proteins in solution

Shiryayev

Pagan

Gunton

et al. 2005

The Journal of Chemical Physics

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The properties of the solvent affect the behavior of the solution. We propose a model that accounts for the contribution of the solvent free energy to the free energy of globular proteins in solution. For the case of an attractive square well potential, we obtain an exact mapping of the phase diagram of this model without solvent to the model that includes the solute-solvent contribution. In particular we find for appropriate choices of parameters upper critical points, lower critical points and even closed loops with both upper and lower critical points, similar to one found before [1]. In the general case of systems whose interactions are not attractive square wells, this mapping procedure can be a first approximation to understand the phase diagram in the presence of solvent. We also present simulation results for both the square well model and a modified Lennard-Jones model.

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A Two-State Model of Hydrophobic Hydration That Produces Compensating Enthalpy and Entropy Changes

Cited by 191 publications

References 35 publications

The impact of urea-induced unfolding on the redox process of immobilised cytochrome c

The impact of urea-induced unfolding on the redox process of immobilised cytochrome c

Heat capacity changes associated with nucleic acid folding

Role of solvent for globular proteins in solution

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