Dresden 2014 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 14: Posters: Protein Structure and dynamics
BP 14.4: Poster
Dienstag, 1. April 2014, 09:30–12:30, P1
Glass-like transition in a dry protein: evidence from neutron scattering study — •A.V. Frontzek1, S.V. Strokov1, J.P. Embs2, and S.G. Lushnikov1 — 1Ioffe Physical Technical Institute, St.Petersburg, Russia — 2Paul Scherrer Institut, Switzerland
The interest in proteins dynamics is stimulated by its close relation to the biological activity and mechanisms of functioning. Generally, biopolymers demonstrate the dynamical features typical for disordered systems. Such phenomena as the dynamical transition and a glass transition in hydrated proteins have been revealed and intensively investigated in past decades. However, it still remained an open question if a glass transition occurs in dry biopolymers. Our purpose was to study the vibrational and relaxational dynamics of two dry model proteins, bovine serum albumin and alpha-lactalbumin form bovine milk, at temperatures at which a glass or dynamical transition can occur (200-340K). The lyophilized powders of both proteins have been used for neutron scattering experiments at a neutron time-of-flight spectrometer FOCUS (SINQ). As a result, the inelastic incoherent dynamic structure factors and the density of states have been obtained and analyzed in broad temperature range. Anomalous temperature behaviour has been revealed for relaxational and low-frequency vibrational dynamics of investigated proteins in the vicinity of 250 K. The mean square atomic displacement has been demonstrated to exhibit a change in the slope of temperature dependence near the same temperature. The presented results point out that the glass-like transition occurs also in dry protein.