title: The influence of water on protein properties.
abstract: The "dynamic" or "glass" transition in biomolecules is as important to their functioning as the folding process. This transition occurs in the low temperature regime and has been related to the onset of biochemical activity that is dependent on the hydration level. This protein transition is believed to be triggered by the strong hydrogen bond coupling in the hydration water. We study the vibrational bending mode and measure it using Fourier Transform Infrared spectroscopy. We demonstrate that at the molecular level the hydration water bending mode bonds the C=O and N-H peptide groups, and find that the temperature of the "dynamic" protein transition is the same as the fragile-to-strong dynamic transition in confined water. The fragile-to-strong dynamic transition in water governs the nature of the H bonds between water and peptides and appears to be universal in supercooled glass-forming liquids.
authors.affiliation: Dipartimento di Fisica e Scienze della Terra, Universit à di Messina, I-98166, Messina, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Mallamace
authors.affiliation: Dipartimento di Chimica and CSGI, Università di Firenze, 50019 Firenze, Italy.
authors.forename: Piero
authors.initials: P
authors.lastname: Baglioni
authors.affiliation: Dipartimento di Fisica e Scienze della Terra, Universit à di Messina, I-98166, Messina, Italy.
authors.forename: Carmelo
authors.initials: C
authors.lastname: Corsaro
authors.affiliation: Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Sow-Hsin
authors.initials: SH
authors.lastname: Chen
authors.affiliation: Dipartimento di Scienze dell'Ambiente, della Sicurezza, del Territorio, degli Alimenti e della Salute, Università di Messina Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Mallamace
authors.affiliation: Consiglio Nazionale delle Ricerche-IPCF, I-98166, Messina, Italy.
authors.forename: Cirino
authors.initials: C
authors.lastname: Vasi
authors.affiliation: Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215, USA.
authors.forename: H Eugene
authors.initials: HE
authors.lastname: Stanley
mesh_terms: D006860:Hydrogen Bonding; D011312:Pressure; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D011506:Proteins; D014867:Water