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MO: Molekülphysik

MO 15: Biomolecules II

MO 15.2: Vortrag

Freitag, 4. März 2005, 17:15–17:30, HU 2097

Structural identification of gas-phase biomolecules using IR spectroscopy — •Joost M. Bakker^1,2, Isabelle Compagnon¹, Gert von Helden², Jos Oomens¹, and Gerard Meijer² — ¹FOM Institute for Plasma Physics Rijnhuizen, Nieuwegein, The Netherlands — ²Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin

For biologically relevant molecules, the primary structure can nowadays be obtained in a rather routine fashion, making use of techniques such as mass spectrometry and electrophoresis. The secondary and higher orders structures, i.e. the three dimensional structure, of such systems are much harder to obtain, however. Since the secondary structure is a decisive factor in the biological function of the species, it is of great interest to study the fundamental interactions that determine the shape of the molecule. In gas-phase experiments the influences of a solvating medium are eliminated, so a careful study of these inter- and intramolecular interactions is possible.

Here, we present results of studies of gas-phase biomolecules using infrared (IR) ion-dip spectroscopy. Using this double-resonance technique, IR spectra of cold, well defined structural conformers can be measured. IR excitation of the molecules of interest is performed with mid-IR radiation (5–40 µm) produced by the Free-Electron Laser for Infrared eXperiments (FELIX) in Nieuwegein, the Netherlands, followed by UV ionization. Among systems that are studied are small tryptophan containing peptides, the gas-phase nucleobase pair guanine-cytosine and a model di-saccharide: lactose.