title: Hydration water rotational motion as a source of configurational entropy driving protein dynamics. Crossovers at 150 and 220 K.
abstract: The existence of a protein dynamic transition around 220 K is widely known and the central role of the protein hydration shell is now largely recognized as the driving force for this transition. In this paper, we propose a mechanism, at the molecular level, for the contribution of hydration water. In particular, we identify the key importance of rotational motion of the hydration water as a source of configurational entropy triggering (i) the 220 K protein dynamic crossover (the so-called dynamic transition) but also (ii) a much less intense and scarcely reported protein dynamic crossover, associated to a calorimetric glass transition, at 150 K.
authors.affiliation: Commissariat à l'Energie Atomique, IRAMIS, Laboratoire Léon Brillouin, CEA Saclay, Gif-sur-Yvette, France. jmzanotti@cea.fr
authors.forename: J-M
authors.initials: JM
authors.lastname: Zanotti
authors.forename: G
authors.initials: G
authors.lastname: Gibrat
authors.forename: M-C
authors.initials: MC
authors.lastname: Bellissent-Funel