title: Thermal stability limits of proteins in solution and adsorbed on a hydrophobic surface.
abstract: A coarse-grained Monte Carlo simulation is used to study thermal denaturation of small proteins in an infinitely dilute solution and adsorbed on a flat hydrophobic surface. Intermolecular interactions are modeled using the Miyazawa-Jernigan (MJ) knowledge-based potential for implicit solvent with the BULDG hydrophobicity scale. We analyze the thermal behavior of lysozyme for its prevalence of α-helices, fibronectin for its prevalence of β-sheets, and a short single helical peptide. Protein dimensions and contact maps are studied in detail before and during isothermal adsorption and heating. The MJ potential is shown to correctly predict the native conformation in solution under standard conditions, and the anticipated thermal stabilization of adsorbed proteins is observed when compared with heating in solution. The helix of the peptide is found to be much less stable thermally than the helices of lysozyme, reinforcing the importance of long-range forces in defining the protein structure. Contact map analysis of the adsorbed proteins shows correlation between the hydrophobicity of the secondary structure and their thermal stability on the surface.
authors.affiliation: Department of Chemical Engineering, Technion - Israel Institute of Technology, Haifa, Israel 32000.
authors.forename: Yevgeny
authors.initials: Y
authors.lastname: Moskovitz
authors.forename: Simcha
authors.initials: S
authors.lastname: Srebnik
mesh_terms: D000327:Adsorption; D004795:Enzyme Stability; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D008958:Models, Molecular; D009010:Monte Carlo Method; D009113:Muramidase / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D012996:Solutions; D013499:Surface Properties; D013696:Temperature
chemical_list: D008051:Lipid Bilayers; D010446:Peptide Fragments; D012996:Solutions; D009113:Muramidase