Thermodynamic destabilization of azurin by four different tetramethylguanidinium amino acid ionic liquids.

Autor: DeStefano I; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA., DeStefano G; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA., Paradis NJ; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA., Patel R; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA., Clark AK; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA., Gogoj H; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA., Singh G; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA., Jonnalagadda KS; Department of Biological Sciences, Rowan University, Glassboro, NJ 08028, USA; Bantivoglio Honors College, Rowan University, Glassboro, NJ 08028, USA., Patel AY; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA., Wu C; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA; Department of Molecular and Cellular Biosciences, Rowan University, Glassboro, NJ 08028, USA., Caputo GA; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA; Department of Molecular and Cellular Biosciences, Rowan University, Glassboro, NJ 08028, USA., Vaden TD; Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA. Electronic address: vadent@rowan.edu.
Jazyk: angličtina
Zdroj: International journal of biological macromolecules [Int J Biol Macromol] 2021 Jun 01; Vol. 180, pp. 355-364. Date of Electronic Publication: 2021 Mar 17.
DOI: 10.1016/j.ijbiomac.2021.03.090
Abstrakt: The thermal unfolding of the copper redox protein azurin was studied in the presence of four different amino acid-based ionic liquids (ILs), all of which have tetramethylguanidium as cation. The anionic amino acid includes two with alcohol side chains, serine and threonine, and two with carboxylic acids, aspartate and glutamate. Control experiments showed that amino acids alone do not significantly change protein stability and pH changes anticipated by the amino acid nature have only minor effects on the protein. With the ILs, the protein is destabilized and the melting temperature is decreased. The two ILs with alcohol side chains strongly destabilize the protein while the two ILs with acid side chains have weaker effects. Unfolding enthalpy (ΔH unf ° ) and entropy (ΔS unf ° ) values, derived from fits of the unfolding data, show that some ILs increase ΔH unf ° while others do not significantly change this value. All ILs, however, increase ΔS unf ° . MD simulations of both the folded and unfolded protein conformations in the presence of the ILs provide insight into the different IL-protein interactions and how they affect the ΔH unf ° values. The simulations also confirm that the ILs increase the unfolded state entropies which can explain the increased ΔS unf ° values.
(Copyright © 2021 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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