Darstellung und Charakterisierung von Kofaktoren des Elektronentransfers in artifizieller und nativer Proteinumgebung
The protein Myoglobin was used as matix-molecule to produce monomeric porphyrins in solution. The protein complexes of differen zinc pheophorbides and zinc protoporphyrin have been studied by UV/Vis and NMR spectroscopy. The protein stability versus unfolding and NMR results Based on quantum mechanical calculations analysis of EPR- and ENDOR-spectra of the light excited triplet state yielded identification of α-protons and methyl β-protons have been identified for the first time. The data acquired agrees well with previously published data on native reaction centers. The terminal electron acceptors, [4Fe4S] centers FA and FB in Photosystem I (PSI), have been modelled by peptides with 16 amino acid length synthezied by SPPS Fmoc strategy. Both peptides incorporated a [4Fe4S] cluster in oxidation state 2 /1 as prooven by UV/Vis, EPR and Mössbauer spectroscopy. The redoxpotential for the one electron reduction was found to be -470 mV for both modell peptides.