Frankfurt 2006 – wissenschaftliches Programm

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MO: Molekülphysik

MO 41: Hauptvortr
äge

MO 41.4: Hauptvortrag

Mittwoch, 15. März 2006, 12:10–12:40, H12

Peptides and peptide aggregates in the gas phase: what do we learn from isomer selective IR/UV spectroscopy — •Markus Gerhards — H.-Heine Universität Düsseldorf, Institut für Physikalische Chemie I, Universitätsstraße 26.33.O2, 40225 Düsseldorf

Secondary structures play an important role to explain the function of proteins. There are different important binding motifs like β-sheets, α-helices, β-turns or γ-turns. These structures are stabilized by intra- or intermolecular hydrogen bonds. In order to figure out the influence on structure and individual hydrogen bonds upon aggregation with water and to learn more about the driving forces to form secondary structures, isolated di- up to pentapeptides and peptide aggregates are analyzed by mass-, isomer-, and state-selective combined IR/UV techniques, i.e. for each isomer of a given peptide the individual IR spectrum can be recorded in a molecular beam experiment. In combination with force field and ab initio calculations the IR spectra yield the structural binding motif and the strength of the hydrogen bonds. By adding water gradually the influence of a microsolvation shell on the secondary structure can be investigated. Not only water but also templates can form aggregates with peptides. The chosen templates are important to inhibit pathogenic β-sheets, especially the aggregation of templates to a peptide sequence responsible for Alzheimer disease will be discussed.