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Research Paper | Chemical Sciences | Volume 5 Issue 5, May 2016 | Pages: 2528 - 2532 | India
Spectroscopic and Thermodynamic Characterization of Aromatic Amino Acid Behavior in Denaturing Solvent Systems
Abstract: Aromatic amino acids are the principal intrinsic chromophores and fluorophores of proteins, and their optical and thermal signatures provide some of the most information-rich probes available for studying denaturant-induced unfolding. This paper reviews how ultraviolet visible (UV-Vis) absorption, steady-state and time-resolved fluorescence, circular dichroism (CD), and calorimetric techniques (differential scanning calorimetry and isothermal titration calorimetry) are used, individually and in combination, to characterize the structural and energetic consequences of exposing tryptophan, tyrosine, and phenylalanine side chains to urea and guanidinium hydrochloride. We discuss the physical basis for denaturant-induced spectral shifts and quenching, the interpretation of near UV CD as a fingerprint of tertiary packing around aromatic clusters, the extraction of thermodynamic parameters from calorimetric denaturation curves, and the linear extrapolation method used to connect spectroscopic unfolding curves to standard free energies of unfolding. Representative case studies from well-characterized model proteins illustrate how multi-technique integration resolves ambiguities that no single method can address alone.
Keywords: fluorescence spectroscopy, circular dichroism, differential scanning calorimetry, isothermal titration calorimetry, tryptophan fluorescence, protein denaturation
How to Cite?: Naseem Ahmed, "Spectroscopic and Thermodynamic Characterization of Aromatic Amino Acid Behavior in Denaturing Solvent Systems", Volume 5 Issue 5, May 2016, International Journal of Science and Research (IJSR), Pages: 2528-2532, https://www.ijsr.net/getabstract.php?paperid=SR16504090717, DOI: https://dx.doi.org/10.21275/SR16504090717