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Photocycle dynamics of the E149A mutant of cryptochrome 3 from Arabidopsis thaliana

Paper ID Volume ID Publish Year Pages File Format Full-Text
31106 44544 2009 15 PDF Available
Title
Photocycle dynamics of the E149A mutant of cryptochrome 3 from Arabidopsis thaliana
Abstract

The E149A mutant of the cryDASH member cryptochrome 3 (cry3) from Arabidopsis thaliana was characterized in vitro by optical absorption and emission spectroscopic studies. The mutant protein non-covalently binds the chromophore flavin adenine dinucleotide (FAD). In contrast to the wild-type protein it does not bind N5,N10-methenyl-5,6,7,8-tetrahydrofolate (MTHF). Thus, the photo-dynamics caused by FAD is accessible without the intervening coupling with MTHF. In dark adapted cry3-E149A, FAD is present in the oxidized form (FADox), semiquinone form (FADH), and anionic hydroquinone form (FADredH−). Blue-light photo-excitation of previously unexposed cry3-E149A transfers FADox to the anionic semiquinone form (FAD−) with a quantum efficiency of about 2% and a back recovery time of about 10 s (photocycle I). Prolonged photo-excitation leads to an irreversible protein re-conformation with structure modification of the U-shaped FAD and enabling proton transfer. Thus, a change in the photocycle dynamics occurs with photo-conversion of FADox to FADH, FADH to FADredH−, and thermal back equilibration in the dark (photocycle II). The photocycle dynamics of cry3-E149A is compared with the photocycle behaviour of wild-type cry3 and other photo-sensory cryptochromes.

Keywords
Cryptochrome cry3; Cryptochrome mutant; Arabidopsis thaliana; Blue-light photoreceptor, DNA-photolyase, flavin adenine dinucleotide (FAD); Photocycle dynamics; Photo-induced charge transfer, FAD reduction and oxidation
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Photocycle dynamics of the E149A mutant of cryptochrome 3 from Arabidopsis thaliana
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 97, Issue 2, 9 November 2009, Pages 94–108
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