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Research Paper | Chemical Sciences | Volume 7 Issue 3, March 2018 | Pages: 1984 - 1988 | India
Influence of Chemical Denaturants on Solute Solvent Interactions of Aromatic Amino Acids During Protein Unfolding
Abstract: Chemical denaturants such as urea and guanidinium hydrochloride (GdnHCl) are the most widely used tools for probing protein stability, yet the molecular basis of their action remains an active area of investigation. Because aromatic amino acids tryptophan, tyrosine, and phenylalanine carry large, polarizable side chains that are simultaneously hydrophobic and capable of specific electrostatic interactions, they are exceptionally sensitive reporters of how denaturants reorganize the solvent shell around a protein during unfolding. This paper reviews the mechanisms by which urea and GdnHCl alter solute solvent interactions of aromatic residues, integrating the direct-binding and indirect (water structure perturbation) models, preferential interaction thermodynamics, and transfer free energy data. We examine how denaturant molecules compete with water for access to aromatic ring surfaces, how this competition changes local hydration numbers and dielectric environment, and how cation?? and ??? contacts are modulated as the protein backbone becomes more solvent-exposed. The synthesis presented here supports a hybrid mechanism in which direct denaturant aromatic ring stacking dominates at the residue level, while bulk solvent reorganization contributes a smaller, cooperative component to net unfolding thermodynamics.
Keywords: urea, guanidinium hydrochloride, aromatic amino acids, protein unfolding, preferential interaction, hydration shell
How to Cite?: Naseem Ahmed, "Influence of Chemical Denaturants on Solute Solvent Interactions of Aromatic Amino Acids During Protein Unfolding", Volume 7 Issue 3, March 2018, International Journal of Science and Research (IJSR), Pages: 1984-1988, https://www.ijsr.net/getabstract.php?paperid=SR18304090305, DOI: https://dx.doi.org/10.21275/SR18304090305