title: Protein remains stable at unusually high temperatures when solvated in aqueous mixtures of amino acid based ionic liquids.
abstract: Using molecular dynamics simulations, we investigated the thermal stability and real-time denaturation of a model mini-protein in four solvents: (1) water, (2) 1-ethyl-3-methylimidazolium alaninate [EMIM][ALA] (5 mol% in water), (3) methioninate [EMIM][MET] (5 mol% in water), and (4) tryptophanate [EMIM][TRP] (5 mol% in water). Upon analyzing the radius of gyration, the solvent-accessible surface area, root-mean-squared deviations, and inter- and intramolecular hydrogen bonds, we found that the mini-protein remains stable at 30-40 K higher temperatures in aqueous amino acid based ionic liquids (AAILs) than in water. This thermal stability was correlated with the thermodynamics and shear viscosity of the AAIL-containing mixtures. These results suggest that AAILs are generally favorable for protein conservation. Graphical Abstract Conformation of the [TRP]-cage mini-protein in an aqueous amino acid based ionic liquid (AAIL).
authors.affiliation: Department of Physics, Chemistry and Pharmacy, MEMPHYS-Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Chevrot
authors.affiliation: Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, 12231-280, São José dos Campos, SP, Brazil. fileti@gmail.com.
authors.forename: Eudes Eterno
authors.initials: EE
authors.lastname: Fileti
authors.affiliation: Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, 12231-280, São José dos Campos, SP, Brazil.
authors.forename: Vitaly V
authors.initials: VV
authors.lastname: Chaban
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D008956:Models, Chemical; D055550:Protein Stability; D011506:Proteins / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D052578:Ionic Liquids; D011506:Proteins
keywords: Denaturation; Ionic liquid; Molecular dynamics; Protein