title: Cold Denaturation Unveiled: Molecular Mechanism of the Asymmetric Unfolding of Yeast Frataxin.
abstract: What is the mechanism that determines the denaturation of proteins at low temperatures, which is, by now, recognized as a fundamental property of all proteins? We present experimental evidence that clarifies the role of specific interactions that favor the entrance of water into the hydrophobic core, a mechanism originally proposed by Privalov but never proved experimentally. By using a combination of molecular dynamics simulation, molecular biology, and biophysics, we identified a cluster of negatively charged residues that represents a preferential gate for the entrance of water molecules into the core. Even single-residue mutations in this cluster, from acidic to neutral residues, affect cold denaturation much more than heat denaturation, suppressing cold denaturation at temperatures above zero degrees. The molecular mechanism of the cold denaturation of yeast frataxin is intrinsically different from that of heat denaturation.
authors.affiliation: Department of Basic and Clinical Neurosciences, Kings College London, London, SE5 9RX, UK.
authors.forename: Domenico
authors.initials: D
authors.lastname: Sanfelice
authors.affiliation: Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100, Siena, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Morandi
authors.affiliation: Department of Basic and Clinical Neurosciences, Kings College London, London, SE5 9RX, UK. annalisa.1.pastore@kcl.ac.uk.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Pastore
authors.affiliation: Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100, Siena, Italy.
authors.forename: Neri
authors.initials: N
authors.lastname: Niccolai
authors.affiliation: Department of Basic and Clinical Neurosciences, Kings College London, London, SE5 9RX, UK. temussi@unina.it.|Department of Chemical Sciences, Università di Napoli Federico II, via Cinthia, 80126, Napoli, Italy. temussi@unina.it.
authors.forename: Piero Andrea
authors.initials: PA
authors.lastname: Temussi
mesh_terms: D003080:Cold Temperature; D033862:Iron-Binding Proteins / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D011489:Protein Denaturation; D058767:Protein Unfolding; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D000096923:Frataxin
chemical_list: D033862:Iron-Binding Proteins; D014867:Water; D000096923:Frataxin
keywords: cold denaturation; electrostatic frustration; hydration; hydrophobic effect; protein folding