title: Experimental free energy surfaces reveal the mechanisms of maintenance of protein solubility.
abstract: The identification of the factors that enable normally folded proteins to remain in their soluble and functional states is crucial for a comprehensive understanding of any biological system. We have determined a series of energy landscapes of the acylphosphatase from Drosophila melanogaster under a variety of conditions by combining NMR measurements with restrained molecular dynamics simulations. We thus analyzed the differences in the structures, dynamics, and energy surfaces of the protein in its soluble state or in situations where it aggregates through conformational states that have native-like structure, folding stability, and enzymatic activity. The study identifies the nature of the energy barriers that under normal physiological conditions prevent the protein ensemble from populating dangerous aggregation-prone states. We found that such states, although similar to the native conformation, have altered surface charge distribution, alternative topologies of the β-sheet region, and modified solvent exposure of hydrophobic surfaces and aggregation-prone regions of the sequence. The identified barriers allow the protein to undergo functional dynamics while remaining soluble and without a significant risk of misfolding and aggregation into nonfunctional and potentially toxic species.
authors.affiliation: Division of Molecular Biosciences, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: Alfonso
authors.initials: A
authors.lastname: De Simone
authors.forename: Anne
authors.initials: A
authors.lastname: Dhulesia
authors.forename: Gemma
authors.initials: G
authors.lastname: Soldi
authors.forename: Michele
authors.initials: M
authors.lastname: Vendruscolo
authors.forename: Shang-Te Danny
authors.initials: ST
authors.lastname: Hsu
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Chiti
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Dobson
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000737:chemistry*; D000818:Animals; D004331:Drosophila melanogaster / Q000201:enzymology*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D011487:Protein Conformation; D012995:Solubility; D000097024:Acylphosphatase
chemical_list: D017766:Acid Anhydride Hydrolases; D000097024:Acylphosphatase