Correlating solvation with conformational pathways of proteins in alcohol–water mixtures: a THz spectroscopic insight
| Autor: | Rajib Kumar Mitra, Himanshu Gohil, S. S. Prabhu, Debasish Das Mahanta, Partha Pyne |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Terahertz Spectroscopy
Circular dichroism Aqueous solution Ethanol Protein Conformation Terahertz radiation Solvation Water General Physics and Astronomy Alcohol Lactoglobulins Trifluoroethanol Protein Structure Secondary chemistry.chemical_compound Solubility chemistry Chemical physics Attenuation coefficient Biophysical Process Animals Cattle Muramidase Physical and Theoretical Chemistry Absorption (chemistry) Chickens |
| Zdroj: | Physical Chemistry Chemical Physics. 23:17536-17544 |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/d1cp01841h |
| Popis: | Water, being an active participant in most of the biophysical processes, is important to trace how protein solvation changes as its conformation evolves in the presence of solutes or co-solvents. In this study, we investigate how the secondary structures of two diverse proteins - lysozyme and β-lactoglobulin - change in the aqueous mixtures of two alcohols - ethanol and 2,2,2-trifluoroethanol (TFE) using circular dichroism measurements. We observe that these alcohols change the secondary structures of these proteins and the changes are protein-specific. Subsequently, we measure the collective solvation dynamics of these two proteins both in the absence and in the presence of alcohols by measuring the frequency-dependent absorption coefficient (α(ν)) in the THz (0.1-1.2 THz) frequency domain. The alcohol-water mixtures exhibit a non-ideal behaviour with the highest absorption difference (Δα) obtained at Xalcohol = 0.2. The protein solvation in the presence of the alcohols shows an oscillating behaviour in which Δαprotein changes with Xalcohol. Such an oscillatory behaviour of protein solvation results from a delicate interplay between the protein-water, protein-alcohol and water-alcohol associations. We attempt to correlate the various structural conformations of the proteins with the associated solvation. |
| Databáze: | OpenAIRE |
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