Dresden 2014 – scientific programme

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BP: Fachverband Biologische Physik

BP 28: Protein structure and dynamics II

BP 28.6: Talk

Wednesday, April 2, 2014, 16:30–16:45, HÜL 386

Terahertz spectroscopy on amino acids — •Sebastian Emmert, Martin Wolf, Peter Lunkenheimer, and Alois Loidl — Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, Germany

All known proteins are built up from a set of 23 standard amino acids. Their three-dimensionally folded structure is mainly determined by the non-covalent interactions of the amino acid residues, such as hydrogen bonds. Therefore it is crucial to study the binding abilities and vibrational properties of these basic building blocks, to achieve a better understanding of the dynamics of the biological macromolecules.

With the novel technique of terahertz time-domain spectroscopy the interesting, but only rarely explored spectral region between the dielectric and the optical frequency regime can be covered. The amino acids in their crystalline state show numerous characteristic resonant features in the range 0.2 THz to 5 THz. It is shown that only by a thorough investigation of the temperature evolution of these spectral features and by a comparison with additional experimentally and theoretically obtained data, a complete assignment of all resonances is made possible. For this purpose, spectra of various amino acids were measured in the temperature range 4 K to 300 K. Fits were performed to quantify the temperature-induced shifts and intensity variations. In this way, spectral contributions from intra- and intermolecular vibrations could be separated by means of their anharmonicity and the dynamics of specific functional groups could be studied.