Shirdel, J. and Zirak, P. and Penzkofer, Alfons and Breitkreuz, H. and Wolf, E. (2008) Absorption and fluorescence spectroscopic characterisation of the circadian blue-light photoreceptor cryptochrome from Drosophila melanogaster (dCry). CHEMICAL PHYSICS, 352 (1-3). pp. 35-47. ISSN 0301-0104, 1873-4421
Full text not available from this repository. (Request a copy)Abstract
The absorption and fluorescence behaviour of the circadian blue-light photoreceptor cryptochrome from Drosophila melanogaster (dCry) in a pH 8 aqueous buffer solution is studied. The flavin adenine dinucleotide (FAD) cofactor of dCry is identified to be present in its oxidized form (FAD(ox)), and the 5,10-methenyltetrahydrofolate (MTHF) cofactor is found to be hydrolyzed and oxidized to 10-formyldihydrofolate (10-FDHF). The absorption and the fluorescence behaviour of dCry is investigated in the dark-adapted (receptor) state, the light-adapted (signalling) state, and under long-time violet light exposure. Photoexcitation of FAD(ox) in dCry causes a reductive electron transfer to the formation of anionic FAD semiquinone (FAD(center dot-)), and photo-excitation of the generated FAD(center dot-) causes an oxidative electron transfer to the back formation of FAD(ox). In light adapted dCry a photo-induced equilibrium between FAD(ox) and FAD(center dot-)exists. The photo-cycle dynamics of signalling state formation and recovery is discussed. Quantum yields of photo-induced signalling state formation of about 0.2 and of photo-induced back-conversion of about 0.2 are determined. A recovery of FAD(center dot-) to FAD(ox) in the dark with a time constant of 1.6 min at room temperature is found. (C) 2008 Elsevier B.V. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | FLAVIN ADENINE-DINUCLEOTIDE; TIME-RESOLVED FLUORESCENCE; INDUCED ELECTRON-TRANSFER; SYNECHOCYSTIS SP PCC6803; COLI DNA PHOTOLYASE; ARABIDOPSIS-THALIANA; ESCHERICHIA-COLI; CHLAMYDOMONAS-REINHARDTII; RHODOBACTER-SPHAEROIDES; AQUEOUS-SOLUTION; Drosophila cryptochrome dCry; fluorescence quantum yield; fluorescence lifetime; photo-cycle dynamics; flavin adenine dinucleotide (FAD); oxidized FAD; anionic FAD semiquinone; 5,10-methenyltetrahydrofolate (MTHF); 10-formyldihydrofolate (10-FDHF); electron transfer; photo-interconversion |
| Subjects: | 500 Science > 530 Physics 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Group Alfons Penzkofer |
| Depositing User: | Petra Gürster |
| Date Deposited: | 29 Jun 2022 09:35 |
| Last Modified: | 29 Jun 2022 09:35 |
| URI: | https://pred.uni-regensburg.de/id/eprint/30295 |
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