title: A broad glass transition in hydrated proteins.
abstract: We performed Raman and Brillouin scattering measurements to estimate glass transition temperature, T(g), of hydrated protein. The measurements reveal very broad glass transition in hydrated lysozyme with approximate T(g) approximately 180+/-15 K. This result agrees with a broad range of T(g) approximately 160-200 K reported in literature for hydrated globular proteins and stresses the difference between behavior of hydrated biomolecules and simple glass-forming systems. Moreover, the main structural relaxation of the hydrated protein system that freezes at T(g) approximately 180 K remains unknown. We emphasize the difference between the "dynamic transition", known as a sharp rise in mean-squared atomic displacement <r(2)> at temperatures around T(D) approximately 200-230 K, and the glass transition. They have different physical origin and should not be confused.
authors.affiliation: Department of Polymer Science, University of Akron, Akron, OH 44325, USA.
authors.forename: S
authors.initials: S
authors.lastname: Khodadadi
authors.forename: A
authors.initials: A
authors.lastname: Malkovskiy
authors.forename: A
authors.initials: A
authors.lastname: Kisliuk
authors.forename: A P
authors.initials: AP
authors.lastname: Sokolov
mesh_terms: D009113:Muramidase / Q000737:chemistry; D044367:Phase Transition; D011506:Proteins / Q000737:chemistry*; D012542:Scattering, Radiation; D013059:Spectrum Analysis, Raman; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D011506:Proteins; D014867:Water; D009113:Muramidase