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| Home > Publications database > A Novel Photoreaction Mechanism for the Circadian Blue Light Photoreceptor Drosophila Cryptochrome |
| Home > Publications database > A Novel Photoreaction Mechanism for the Circadian Blue Light Photoreceptor Drosophila Cryptochrome |
| Journal Article | PreJuSER-59166 |
; ; ; ; ; ;
2007
Soc.
Bethesda, Md.
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Please use a persistent id in citations: doi:10.1074/jbc.M608872200
Abstract: Cryptochromes are flavoproteins that are evolutionary related to the DNA photolyases but lack DNA repair activity. Drosophila cryptochrome (dCRY) is a blue light photoreceptor that is involved in the synchronization of the circadian clock with the environmental light-dark cycle. Until now, spectroscopic and structural studies on this and other animal cryptochromes have largely been hampered by difficulties in their recombinant expression. We have therefore established an expression and purification scheme that enables us to purify mg amounts of monomeric dCRY from Sf21 insect cell cultures. Using UV-visible spectroscopy, mass spectrometry, and reversed phase high pressure liquid chromatography, we show that insect cell-purified dCRY contains flavin adenine dinucleotide in its oxidized state (FAD(ox)) and residual amounts of methenyltetrahydrofolate. Upon blue light irradiation, dCRY undergoes a reversible absorption change, which is assigned to the conversion of FAD(ox) to the red anionic FAD(.) radical. Our findings lead us to propose a novel photoreaction mechanism for dCRY, in which FAD(ox) corresponds to the ground state, whereas the FAD(.) radical represents the light-activated state that mediates resetting of the Drosophila circadian clock.
Keyword(s): Animals (MeSH) ; Cell Line (MeSH) ; Circadian Rhythm (MeSH) ; Cryptochromes (MeSH) ; DNA Repair (MeSH) ; Deoxyribodipyrimidine Photo-Lyase: chemistry (MeSH) ; Drosophila: chemistry (MeSH) ; Drosophila: metabolism (MeSH) ; Drosophila Proteins: chemistry (MeSH) ; Drosophila Proteins: metabolism (MeSH) ; Flavin-Adenine Dinucleotide: chemistry (MeSH) ; Flavin-Adenine Dinucleotide: metabolism (MeSH) ; Flavoproteins: chemistry (MeSH) ; Flavoproteins: metabolism (MeSH) ; Oxidation-Reduction (MeSH) ; Photochemistry (MeSH) ; Photoreceptor Cells, Invertebrate: chemistry (MeSH) ; Photoreceptor Cells, Invertebrate: metabolism (MeSH) ; Cryptochromes ; Drosophila Proteins ; Flavoproteins ; Flavin-Adenine Dinucleotide ; Deoxyribodipyrimidine Photo-Lyase ; J
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