Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 26: Photobiophysics
BP 26.2: Vortrag
Freitag, 27. März 2009, 11:15–11:30, ZEU 260
Absorption and Fluorescence Spectroscopic Characterisation of the Circadian Blue-Light Photoreceptor Cryptochrome from Drosophila melanogaster (dCry) — •Javid Shirdel1,3, Peyman Zirak1, Alfons Penzkofer1, Helena Breitkreuz2, and Eva Wolf2 — 1Institut II-Physik, Universität Regensburg, D-93053 Regensburg, Germany — 2Max-Planck-Institute of Molecular Physiology, D-44227 Dortmund, Germany — 3Institut für Physik, Carl Von Ossietzky Universität Oldenburg, D-26129 Oldenburg, Germany
Cryptochromes are blue-light sensitive flavoproteins that are related to photolyases, but do not have the DNA repair mechanism of photolyases. They regulate growth and development in plants, regulate circadian rhythms in plants and animals, act as chemical magneto receptors in migratory birds, and are functioning in bacteria and algae. Here we report the absorption and fluorescence behaviour of the circadian blue-light photoreceptor cryptochrome from Drosophila melanogaster (dCry) in a pH 8 aqueous buffer solution. The flavin adenine dinucleotide (FAD) cofactor of dCry is identified to be present in its oxidized form, and the 5,10-methenyltetrahydrofolate (MTHF) cofactor is found to be hydrolyzed and oxidized to 10-formyldihydrofolate (10-FDHF). Photo-excitation of oxidized FAD in dCry causes a reductive electron transfer to the formation of anionic FAD semiquinone, and photo-excitation of the generated anionic FAD semiquinone causes an oxidative electron transfer to the back formation of oxidized FAD.