title: Internal dynamics and protein-matrix coupling in trehalose-coated proteins.
abstract: We review recent studies on the role played by non-liquid, water-containing matrices on the dynamics and structure of embedded proteins. Two proteins were studied, in water-trehalose matrices: a water-soluble protein (carboxy derivative of horse heart myoglobin) and a membrane protein (reaction centre from Rhodobacter sphaeroides). Several experimental techniques were used: Mossbauer spectroscopy, elastic neutron scattering, FTIR spectroscopy, CO recombination after flash photolysis in carboxy-myoglobin, kinetic optical absorption spectroscopy following pulsed and continuous photoexcitation in Q(B) containing or Q(B) deprived reaction centre from R. sphaeroides. Experimental results, together with the outcome of molecular dynamics simulations, concurred to give a picture of how water-containing matrices control the internal dynamics of the embedded proteins. This occurs, in particular, via the formation of hydrogen bond networks that anchor the protein surface to the surrounding matrix, whose stiffness increases by lowering the sample water content. In the conclusion section, we also briefly speculate on how the protein-matrix interactions observed in our samples may shed light on the protein-solvent coupling also in liquid aqueous solutions.
authors.affiliation: Dipartimento di Scienze Fisiche ed Astronomiche, Università di Palermo, Italy. cordone@fisica.unipa.it
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Cordone
authors.forename: Grazia
authors.initials: G
authors.lastname: Cottone
authors.forename: Sergio
authors.initials: S
authors.lastname: Giuffrida
authors.forename: Gerardo
authors.initials: G
authors.lastname: Palazzo
authors.forename: Giovanni
authors.initials: G
authors.lastname: Venturoli
authors.forename: Cristiano
authors.initials: C
authors.lastname: Viappiani
mesh_terms: D003198:Computer Simulation; D006418:Heme / Q000737:chemistry*; D006860:Hydrogen Bonding; D007700:Kinetics; D008958:Models, Molecular; D009211:Myoglobin / Q000737:chemistry*; D010782:Photolysis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D012242:Rhodobacter sphaeroides; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014199:Trehalose / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D009211:Myoglobin; D045322:Photosynthetic Reaction Center Complex Proteins; C018013:carboxymyoglobin; D014867:Water; D006418:Heme; D014199:Trehalose