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CPP: Chemische Physik und Polymerphysik

CPP 8: Biological Systems

CPP 8.3: Talk

Wednesday, April 4, 2001, 16:25–16:45, 111

ATR-SPP-UV-Ramanspectroscopy as a Sensitive and Selective Tool for Conformational Analysis of Biological Molecules — •D. Zerulla, G. Isfort, K.-D. Schierbaum, D. Riesner, and A. Otto — Heinrich-Heine-Universität Düsseldorf, AG Physikalische Methoden für Biologie und Medizin, Universitätsstr. 1, D-40225 Düsseldorf, Germany

The analysis of the molecular, conformational changes gives new insights to the understanding of biological processes. Especially in the field of infectious protein diseases like BSE, Scrapie and CJD, it is important to understand the underlaying structural mechanisms of folding on a molecular level. In order to get information from relevant biological systems by a more physical-spectroscopic approach the method needs to be very sensitive (as infectious molecules are difficult to get in high concentrations from in-vivo systems) and extremely selective (in order not to get confused by the numerous other proteins and macromolecules).
Our method of choice is the ATR-SPP-Ramanspectroscopy, which fulfills, in combination with elaborate setups, all above mentioned criteria plus it works without any need for labeling.
The high sensitivity is given by a surface enhanced process: A surface-plasmon-polariton is specifically excited in a thin (10nm), evaporated Al-film. Its evanescent EM-field causes amplified Raman-scattering within 100nm from the Al-surface. The high selectivity is caused by resonant excitation of the π−π^*-transition of the peptide-bonding at 206.5nm. Because of the resonance effects neither the aqueous matrix nor other non-amino molecules disturb the spectra.