title: Thermal stability of matrix protein from Newcastle disease virus.
abstract: The thermal stability of the matrix protein (M protein) of Newcastle disease virus (NDV) has been investigated using high-sensitivity differential scanning calorimetry (DSC) at pH 7.4. The thermal folding/unfolding of M protein at this pH value is a reversible process involving a highly cooperative transition between folded and unfolded monomers with a transition temperature (Tm) of 63 °C, an unfolding enthalpy, ΔH(Tm), of 340 kcal mol(-1), and the difference in heat capacity between the native and denatured states of the protein, ΔCp, of 5.1 kcal K(-1) mol(-1). The heat capacity of the native state of the protein is in good agreement with the values calculated using a structure-based parameterization, whereas the calculated values for the hypothetical fully-unfolded state of the protein is higher than those determined experimentally. This difference between the heat capacity of denatured M protein and the heat capacity expected for an unstructured polypeptide of the same sequence, together with the data derived from the heat-induced changes in the steady-state fluorescence of the protein, indicates that the polypeptide chain maintains a significant amount of residual structure after thermal denaturation.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca, 37007 Salamanca, Spain.
authors.forename: Irene Sánchez
authors.initials: IS
authors.lastname: Morán
authors.forename: Sara
authors.initials: S
authors.lastname: Cuadrado-Castano
authors.forename: Isabel Muñoz
authors.initials: IM
authors.lastname: Barroso
authors.forename: Eduard Ya
authors.initials: EY
authors.lastname: Kostetsky
authors.forename: Galina
authors.initials: G
authors.lastname: Zhadan
authors.forename: Javier
authors.initials: J
authors.lastname: Gómez
authors.forename: Valery L
authors.initials: VL
authors.lastname: Shnyrov
authors.forename: Enrique
authors.initials: E
authors.lastname: Villar
mesh_terms: D002152:Calorimetry, Differential Scanning; D006863:Hydrogen-Ion Concentration; D009522:Newcastle disease virus / Q000737:chemistry*; D055550:Protein Stability; D013816:Thermodynamics; D014763:Viral Matrix Proteins / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D014763:Viral Matrix Proteins
keywords: APS; ASA; DSC; N,N,N′,N′-tetramethyl-ethylenediamine.; NDV; Newcastle disease virus; Newcastle disease virus matrix protein; Structural-based statistical thermodynamic analysis; TEMED; Thermal stability; accessible surface area; ammonium persulfate; differential scanning calorimetry