Berlin 2005 – wissenschaftliches Programm
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AKB: Biologische Physik
AKB 200: Poster Session II
AKB 200.30: Poster
Dienstag, 8. März 2005, 17:00–19:00, Poster TU C
Synthesis and Characterization of De Novo Designed Peptides Modeling the Binding Sites of [4Fe-4S] Clusters in Photosystem I — •Mikhail Antonkine1,2, Christoph Breitenstein2, Boris Epel2, Eckhard Bill2, Wolfgang Gärtner2, John Golbeck3, and Wolfgang Lubitz2 — 1Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany. Tel.: 49 30 838 53047, Fax: 49 30 838 56081. — 2Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, Mülheim an der Ruhr, D-45470, Germany. — 3Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802,USA.
Photosystem I (PS I) is a membrane-bound pigment-protein complex found in photosynthetic organisms. It converts the energy of light into chemical energy. The terminal electron transfer cofactors in PS I are three [4Fe-4S] clusters named Fx, Fa, Fb. The PsaC subunit of PS I harbors binding sites of Fa and Fb clusters. We modeled the binding sites of the [4Fe-4S] clusters Fa and Fb of PsaC by preparing sixteen amino acid peptides. Model peptides incorporate the consensus iron-sulfur binding motif and amino acids from the environment of the respective iron-sulfur cluster. The [4Fe-4S] clusters were successfully incorporated into these model peptides, as shown by their optical absorbance, EPR and Mössbauer spectra. We compare continuous wave and pulsed EPR, Electron Spin Echo Envelope Modulation (ESEEM) and Mössbauer spectra of the model [4Fe-4S] clusters with the respective spectra of Fa and Fb in unbound PsaC and in the fully assembled PS I.