Dresden 2014 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 28: Protein structure and dynamics II

BP 28.4: Vortrag

Mittwoch, 2. April 2014, 16:00–16:15, HÜL 386

Protein dynamical transition * Insights from a combination of neutron scattering and MD simulations — •Kerstin Kämpf and Michael Vogel — Institut für Festkörperphysik, TU Darmstadt

Evaluating the temperature-dependent mean square displacement (MSD) of proteins with neutron scattering (NS) a non-linear increase due to anharmonic dynamics is found well below room temperature [1]. It is still under debate whether this phenomenon, denoted as protein dynamical transition, occurs in one or two steps and whether these steps result from to a true dynamical onset or from local (β-) [2] or structural (α-) [3] relaxations entering the time window. A promising approach to clarify these issues is to combine NS data with MD simulations [4]. Application of such combination to hydrated elastin shows that NS data obtained from backscattering experiments are highly consistent with MD results. We find that anomalous internal protein dynamics, leading to a subdiffusive time dependence of the MSD and a power-law or logarithmic-like decay of correlation functions [5], dominates the findings in the time window of the experiments. The increase of the MSD is thus a signature of the onset of complex internal protein motion.

[1] Doster et al, Nature, 337, 754, (1989).

[2] Capaccioli et al. J. Phys. Chem. B, 111, 8197, (2007).

[3] Doster et al, J. Non-Cryst. Sol., 357, 622, (2011).

[4] Hong et al, Phys. Rev. Lett., 107, 148102, (2011).

[5] Kämpf et al., J. Chem. Phys., 137, 205105, (2012).