Regensburg 2002 – wissenschaftliches Programm

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SYBM: Physik biologischer Materie

SYBM III: HV III

SYBM III.1: Hauptvortrag

Dienstag, 12. März 2002, 11:15–11:45, H37

The interplay of structure, dynamics and function in proteins — •Fritz Parak — Physik - Department E17, TUM, 85747 Garching

The knowledge of the architecture of a protein obtained by X-ray structure determination is an important basis for the understanding of its function. However, it is not sufficient. The structure determination by neutrons yields valuable information on the positions of the hydrogens. Equilibrium fluctuations within a conformation as well as dynamical transitions between conformations play an essential role. For the following discussion, myoglobin serves as a model system. Many results can be generalised for other proteins. Proteins are functional active in a certain temperature regime. Lowering the temperature functional important motions are frozen out. Phonon assisted Mössbauer effect with synchrotron radiation allowed the determination of the phonon density spectrum. The L29W mutant of myoglobin has a reaction rate slowed down by two orders of magnitudes in comparison to the wild type. Therefore, the structural relaxation after the photolysis of a CO ligand could be investigated by X rays in the low temperature and in the physiological temperature regime. A consistent picture of protein dynamics is given.