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BP: Fachverband Biologische Physik

BP 26: Posters II

BP 26.2: Poster

Thursday, February 28, 2008, 17:00–19:30, Poster A

Effect of high pressure on the global and internal dynamics of multimeric proteins studied by quasielastic neutron scattering experiment. — •Marie-Sousai Appavou¹, Sebastian Busch², Wolfgang Doster³, Ana Gaspar², and Tobias Unruh² — ¹Forschungszentrum Jülich GmbH, IFF-JCNS, Garching, Germany — ²Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Garching, Germany — ³Technishe Universität München, Physik Department E 13, Garching, Germany

Pressure is a physical parameter, which in contrast to temperature, allows to separate volume changes from entropic effects. Moreover, pressure is increasingly utilized in the sterilization and bio-conservation processes in food and pharmaceutical industries. In the range up to 2000 bar, essentially association-dissociation phenomena of biomolecular assemblies are observed. The unfolding of monomeric proteins typically requires pressures exceeding 3 kbar. Pressure can also be used to investigate the effect of density changes on molecular motions. Quasi-elastic neutron scattering allows exploring structural fluctuations of proteins on the pico-second time scale. In this contribution we present a series of neutron scattering spectra of hemoglobin and beta-casein as a function of pressure. For this project we have built a new scattering cell with high transmission, which can sustain pressures up to 2000 bar. Dynamic changes as a result of water reorganisation and subunit dissociation will be discussed.