Russia and the U. S. A.

Timasheff, N. S.

doi:10.5840/thought194419271

Cited by 8 publications

(16 citation statements)

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“…1, both with regard to the thermodynamic stability of the species and kinetic barriers of the reactions. 4,8,15,16 Solvent modification can stabilize or destabilize the native fold, [27][28][29][30][31][32][33][34] enhance refolding, 42,43 optimize protein crystallization, 44 disrupt aggregates, 32 or steer the formation of intermediates. 32,45,46 The literature contains many useful, but more-or-less empirical guide lines for solvent optimization.…”

Section: -24mentioning

confidence: 99%

“…32,45,46 The literature contains many useful, but more-or-less empirical guide lines for solvent optimization. 4,8,15,16 Rational strategies for solvent optimization require their molecular understanding.…”

Section: -24mentioning

confidence: 99%

“…Stabilization primarily results from hydrophobic forces and H-bonds, while destabilization is mainly founded in an entropic force due to the loss of configurational freedom of the folded chain. 1 It needs only a moderate environmental stress, such as an increase in temperature 2 or pressure 3 or the addition of a co-solvent, 4,5 to upset this balance. For example, the melting temperatures T m of simple proteins, defined as the temperature at which 50% of the protein molecules are unfolded, rarely exceed 80 1C.…”

Section: Introductionmentioning

confidence: 99%

“…14 Alternatively, one can optimize the solvent environment. 4,15,16 In the latter case low-melting organic salts, called ionic liquids (ILs), [17][18][19][20] are at the forefront of the current research. [21][22][23][24] ILs possess unique properties, such as a very low vapour pressure and high thermal stability.…”

Section: Introductionmentioning

confidence: 99%

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How ionic liquids can help to stabilize native proteins

Weingärtner

Cabrele

Herrmann

2012

Phys. Chem. Chem. Phys.

260

233

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The native state of a globular protein is essential for its biocatalytic function, but is marginally stable against unfolding. While unfolding equilibria are often reversible, folding intermediates and misfolds can promote irreversible protein aggregation into amorphous precipitates or highly ordered amyloid states. Addition of ionic liquids-low-melting organic salts-offers intriguing prospects for stabilizing native proteins and their enzymatic function against these deactivating reaction channels. The huge number of cations and anions that form ionic liquids allows fine-tuning of their solvent properties, which offers robust and efficient strategies for solvent optimization. Going beyond case-by-case studies, this article aims at discussing principles for a rational design of ionic liquid-based formulations in protein chemistry and biocatalysis.

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Section: -24mentioning

confidence: 99%

Section: -24mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

How ionic liquids can help to stabilize native proteins

Weingärtner

Cabrele

Herrmann

2012

Phys. Chem. Chem. Phys.

260

233

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“…This methodology has provided access to novel functional conformations of macromolecules (25,26). Although interpretation of the OSA has been a topic of debate (27)(28)(29)(30)(31), it is well corroborated by physical and structural data (23,32,33). Using this approach, we show here for the first time binding isotherms that support the hypothesis of a DNA-bound monomer, which allows the binding of a second monomer in a cooperative pattern, energetically coupled to protein interaction and thus dimerization, increasing the diversity of mechanisms by which E2 proteins regulates virus infection.…”

Section: Human Papillomavirus (Hpv)mentioning

confidence: 99%

Positive Contribution of Hydration on DNA Binding by E2c Protein from Papillomavirus

Lima

Silva

2004

Journal of Biological Chemistry

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Protein-nucleic acid interactions are responsible for the regulation of key biological events such as genomic transcription and recombination and viral replication. However, the recognition mechanisms involved in these processes are not completely understood. Here, we investigate the dominant forces involved in protein-protein and protein-DNA interactions for the 80-amino-acid C-terminal domain of the E2 protein (E2c) from human papillomavirus (HPV-16). The E2c protein is a homodimer that specifically binds to double-stranded DNA containing the consensus sequence ACCG-N 4 -CGGT, where N is any nucleotide. DNA binding affinity is reduced by lowering water chemical potential, accompanied by an increase in cooperativity. Wyman linkage relations between affinity and water chemical potential indicate that 11 additional water molecules are bound in the formation of the complex between E2c and DNA. Salt dissociation isotherms showed that 10 counterions are released upon association, even at low water activity, indicating that this latter variable does not change the electrostatic component of the interaction. Further analysis demonstrates a strong dependence of cooperativity of binding on the protein concentration. Altogether, these results reveal a novel binding pathway in which the consolidated complex may achieve its final form via a monomer-DNA intermediate, which favors the binding of a second monomer. This molecular mechanism reveals the contributions of multiple conformers in a tight virus genome modulation that seems to be important in the cell infection scenario. Human papillomavirus (HPV)1 is a small nonenveloped double-stranded DNA virus that causes epithelial lesions, which often develop into malignancies (1). The viruses HPV 16, -18, and -31 are denoted high risk HPV since they are directly related to cervical cancer. The regulation of gene expression in virus-infected cells is mediated by the factor E2, which controls the transcription of the HPV gene, including those related to malignant transformation. E2 can act either as an activator or as a repressor, depending on the alternate splicing of the product. Infected cells can be found containing (i) the C-terminal domain (E2c), responsible for DNA binding (2) and dimerization (3); (ii) the E2-E8 splicing product; and (iii) the full E2 protein (E2-full), consisting of the E2c, the N-terminal transactivation domain (E2TA), and an unstructured region with little known function. These three components recognize and bind specifically the palindromic sequence ACCGN 4 CGGT (2), where N is any base, although differences in affinity can arise depending on the N bases (4 -7). Part of the E2 structure has been solved: both for E2c, the DNA-binding domain (7-10), and for the transactivation domain (11,12).Much has appeared in the literature about the behavior of the E2c protein from the high risk HPV-16, in terms of homoassociation (13-16) and DNA binding and recognition, through equilibrium (6, 9, 14, 16 -20) and kinetic assays (4, 21). Although we have previously p...

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Caffeine dimerization: effects of sugar, salts, and water structure

Shimizu

2015

Food Funct.

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Sugars and salts strongly affect the dimerization of caffeine in water. Such a change of dimerization, considered to be crucial for bitter taste suppression, has long been rationalized by the change of "water structure" induced by the additives; "kosmotropic" (water structure enhancing) salts and sugars promote dimerization, whereas "chaotropic" (water structure breaking) salts suppress dimerization. Based on statistical thermodynamics, here we challenge this consensus; we combine the rigorous Kirkwood-Buff theory of solution with the classical isodesmic model of caffeine association. Instead of the change of water structure, we show that the enhancement of caffeine dimerization is due to the exclusion of additives from caffeine, and that the weakening of dimerization is due to the binding of additives on caffeine.

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Russia and the U. S. A.

Cited by 8 publications

References 0 publications

How ionic liquids can help to stabilize native proteins

How ionic liquids can help to stabilize native proteins

Positive Contribution of Hydration on DNA Binding by E2c Protein from Papillomavirus

Caffeine dimerization: effects of sugar, salts, and water structure

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