Dresden 2009 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 5: Proteins

BP 5.5: Vortrag

Montag, 23. März 2009, 15:30–15:45, ZEU 260

Hydration and Temperature dependent far-infrared Investigations on Proteins — Christian U. Stehle, Wasim Abuillan, •Bruno Gompf, and Martin Dressel — 1. Physikalisches Institut, Universität Stuttgart

Besides the well studied mid-infrared region with sharp absorption bands, little work has been done on proteins in the far-infrared, where they have several broad absorption bands. Extensive investigations on proteins with a high reproducibility and defined temperature/humidity have been made from 65cm-1 to 690cm-1. Several bands in the spectra of different proteins have been found in comparison to the featureless THz studies, where a protein distinction is not possible up to now. We identified the basic absorption frequencies and found at least one band that seems to be common in all proteins, which is not one of the known amide bands. Via the sorption isotherm equation the protein hydration process could be quantified and compared to the spectra, which show just small hydration dependence. This reveals that protein bound water molecules absorb much less and different than liquid water molecules. The temperature dependence shows a strong over all decrease of absorption with rising temperature. An additional frequency dependent effect especially of the low frequency band around 200cm-1 has been found.