title: Structure and dynamics of high molecular weight glutenin subunits of durum wheat (Triticum durum) in water and alcohol solutions studied by electron paramagnetic resonance and circular dichroism spectroscopies.
abstract: Complementary information on the structure and dynamics of high molecular weight glutenin subunits (HMW-GS) of durum wheat (Triticum durum) was obtained by means of two spectroscopic techniques. Electron paramagnetic resonance was used to investigate the dynamics of the HMW-GS hydrated with two 2-propanol/water mixtures at temperatures between 268 and 308 K by specific spin labeling of their cysteine residues. Spectra were of a composite type, resulting from two populations of spin labels differing in molecular mobility, both undergoing isotropic rotational diffusion. Diffusional coefficients and populations of the fast- and slow-moving spin labels, determined by an accurate spectral line shape analysis, are discussed as a function of temperature and water content in the solvent systems. Far-UV circular dichroism was employed to provide information on the secondary structure of the HMW-GS in three different solvents [aqueous 50% (v/v) 2-propanol, aqueous 0.1% (v/v) trifluoroacetic acid, and trifluoroethanol]. For the first one, the influence of temperature on HMW-GS structure was also investigated.
authors.affiliation: Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via Risorgimento 35, I-56126 Pisa, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Calucci
authors.forename: C
authors.initials: C
authors.lastname: Pinzino
authors.forename: A
authors.initials: A
authors.lastname: Capocchi
authors.forename: L
authors.initials: L
authors.lastname: Galleschi
authors.forename: S
authors.initials: S
authors.lastname: Ghiringhelli
authors.forename: F
authors.initials: F
authors.lastname: Saviozzi
authors.forename: M
authors.initials: M
authors.lastname: Zandomeneghi
mesh_terms: D019840:2-Propanol; D019342:Acetic Acid; D002942:Circular Dichroism; D004578:Electron Spin Resonance Spectroscopy; D005983:Glutens / Q000031:analogs & derivatives* / Q000737:chemistry*; D008970:Molecular Weight; D012996:Solutions; D013113:Spin Labels; D013696:Temperature; D013816:Thermodynamics; D014908:Triticum / Q000737:chemistry*; D014867:Water
chemical_list: D012996:Solutions; D013113:Spin Labels; D014867:Water; D005983:Glutens; C037302:glutenin; D019840:2-Propanol; D019342:Acetic Acid