Dresden 2006 – wissenschaftliches Programm
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AKB: Biologische Physik
AKB 30: Poster Session I
AKB 30.10: Poster
Montag, 27. März 2006, 15:30–18:00, P1
Electronic structure of surface-layer proteins probed by resonant photoemission — •Denis Vyalikh1, Vlodimir Maslyuk2, Andreas Kade1, Steffen Danzenbächer1, Alexandr Kirchner3, Yuri Dedkov1, Michael Mertig3, Ingrid Mertig2, and Serguei Molodtsov1 — 1Institut für Festkörperphysik, TU Dresden, D-01062 Dresden — 2Martin-Luther-Universität Halle-Wittenberg, Fachbereich Physik, D-06099 Halle — 3Max-Bergmann-Zentrum für Biomaterialien and Institut für Werkstoffwissenschaft, TU Dresden, D-01062 Dresden
The electronic structure of the regular, two-dimensional surface-layer proteins (S layer) of Bacillus sphaericus NCTC 9602 has been examined by conventional and resonant photoemission (PE), near-edge x-ray absorption fine structure (NEXAFS) spectroscopy. The results were compared with density-functional theory (DFT) calculations using a linear combination of atomic orbitals (LCAO) approach. It is demonstrated that a series of characteristic NEXAFS peaks can be assigned to particular molecular orbitals of the amino acids using a phenomenological building-block model. Applying this model, lineshape evaluation of the core-level PE spectra can successfully be used for quantitative chemical analysis of the protein structure. We have demonstrated that by tuning the photon energy in the vicinity of the C 1s absorption edge, strong changes in intensity of the resonant PE peaks corresponding to participator decay channels are observed. Thus, an interpretation of valence electronic states is achieved experimentally from resonant decay spectra that also is in a good agreement with our DFT-LCAO calculations.