title: Adsorption and Unfolding of Lysozyme at a Polarized Aqueous-Organic Liquid Interface.
abstract: The adsorption of proteins at the interface between two immiscible electrolyte solutions has been found to be key to their bioelectroactivity at such interfaces. Combined with interfacial complexation of organic phase anions by cationic proteins, this adsorption process may be exploited to achieve nanomolar protein detection. In this study, replica exchange molecular dynamics simulations have been performed to elucidate for the first time the molecular mechanism of adsorption and subsequent unfolding of hen egg white lysozyme at low pH at a polarized 1,2-dichloroethane/water interface. The unfolding of lysozyme was observed to occur as soon as it reaches the organic-aqueous interface, which resulted in a number of distinct orientations at the interface. In all cases, lysozyme interacted with the organic phase through regions rich in nonpolar amino acids, such that the side chains are directed toward the organic phase, whereas charged and polar residues were oriented toward the aqueous phase. By contrast, as expected, lysozyme in neat water at low pH does not exhibit significant structural changes. These findings demonstrate the key influence of the organic phase upon adsorption of lysozyme under the influence of an electric field, which results in the unfolding of its structure.
authors.affiliation: School of Biomedical Sciences, CHIRI Biosciences and Curtin Institute for Computation, ‡Department of Chemistry and Nanochemistry Research Institute, Curtin University , GPO Box U1987, Perth, WA 6845, Australia.
authors.forename: Mahreen
authors.initials: M
authors.lastname: Arooj
authors.affiliation: School of Biomedical Sciences, CHIRI Biosciences and Curtin Institute for Computation, ‡Department of Chemistry and Nanochemistry Research Institute, Curtin University , GPO Box U1987, Perth, WA 6845, Australia.
authors.forename: Neha S
authors.initials: NS
authors.lastname: Gandhi
authors.affiliation: School of Biomedical Sciences, CHIRI Biosciences and Curtin Institute for Computation, ‡Department of Chemistry and Nanochemistry Research Institute, Curtin University , GPO Box U1987, Perth, WA 6845, Australia.
authors.forename: Cara A
authors.initials: CA
authors.lastname: Kreck
authors.affiliation: School of Biomedical Sciences, CHIRI Biosciences and Curtin Institute for Computation, ‡Department of Chemistry and Nanochemistry Research Institute, Curtin University , GPO Box U1987, Perth, WA 6845, Australia.
authors.forename: Damien W M
authors.initials: DW
authors.lastname: Arrigan
authors.affiliation: School of Biomedical Sciences, CHIRI Biosciences and Curtin Institute for Computation, ‡Department of Chemistry and Nanochemistry Research Institute, Curtin University , GPO Box U1987, Perth, WA 6845, Australia.
authors.forename: Ricardo L
authors.initials: RL
authors.lastname: Mancera
mesh_terms: D000327:Adsorption; D005025:Ethylene Dichlorides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D056004:Molecular Dynamics Simulation; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D058767:Protein Unfolding; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D005025:Ethylene Dichlorides; D014867:Water; C024565:ethylene dichloride; D009113:Muramidase