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Absorption and fluorescence spectroscopic characterization of cryptochrome 3 from Arabidopsis thaliana

Paper ID Volume ID Publish Year Pages File Format Full-Text
31207 44568 2006 16 PDF Available
Title
Absorption and fluorescence spectroscopic characterization of cryptochrome 3 from Arabidopsis thaliana
Abstract

The blue light photoreceptor cryptochrome 3 (cry3) from Arabidopsis thaliana was characterized at room temperature in vitro in aqueous solution by optical absorption and emission spectroscopic studies. The protein non-covalently binds the chromophores flavin adenine dinucleotide (FAD) and N5,N10-methenyl-5,6,7,8-tetrahydrofolate (MTHF). In the dark-adapted state of cry3, the bound FAD is present in the oxidized form (FADox, ca. 38.5%), in the semiquinone form (FADH, ca. 5%), and in the fully reduced neutral form (FADredH2) or fully reduced anionic form (FADredH−, ca. 55%). Some amount of FAD (ca. 1.5%) in the oxidized state remains unbound probably caused by chromophore release and/or denaturation. Förster-type energy transfer from MTHF to FADox is observed. Photo-excitation reversibly modifies the protein conformation causing a slight rise of the MTHF absorption strength and an increase of the MTHF fluorescence efficiency (efficient protein conformation photo-cycle). Additionally there occurs reversible reduction of bound FADox to FADredH2 (or FADredH−, FADox photo-cycle of moderate efficiency), reversible reduction of FADH to FADredH2 (or FADredH−, FADH photo-cycle of high efficiency), and modification of re-oxidable FADredH2 (or FADredH−) to permanent FADredH2 (or FADredH−) with low quantum efficiency. Photo-excitation of MTHF causes the reversible formation of a MTHF species (MTHF′, MTHF photo-cycle, moderate quantum efficiency) with slow recovery to the initial dark state, and also the formation of an irreversible photoproduct (MTHF″).

Keywords
Cryptochrome; Arabidopsis thaliana; Cry3; MTHF; FAD; Fluorescence spectroscopy; Absorption spectroscopy; MTHF–FAD interaction; Photo-reduction; Photo-cycle dynamics; Energy transfer
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Absorption and fluorescence spectroscopic characterization of cryptochrome 3 from Arabidopsis thaliana
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 85, Issue 1, 2 October 2006, Pages 1–16
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us