Cryptochromes are almost ubiquitous blue-light receptors and act in several species as central components of the circadian clock. Despite being evolutionary and structurally related with DNA photolyases, a class of light-driven DNA-repair enzymes, and having similar cofactor compositions, cryptochromes lack DNA-repair activity ...
Cryptochromes are almost ubiquitous blue-light receptors and act in several species as central components of the circadian clock. Despite being evolutionary and structurally related with DNA photolyases, a class of light-driven DNA-repair enzymes, and having similar cofactor compositions, cryptochromes lack DNA-repair activity. Cryptochrome 3 from the plant Arabidopsis thaliana belongs to the DASH-type subfamily. Its crystal structure determined at 1.9 Angstroms resolution shows cryptochrome 3 in a dimeric state with the antenna cofactor 5,10-methenyltetrahydrofolate (MTHF) bound in a distance of 15.2 Angstroms to the U-shaped FAD chromophore. Spectroscopic studies on a mutant where a residue crucial for MTHF-binding, E149, was replaced by site-directed mutagenesis demonstrate that MTHF acts in cryptochrome 3 as a functional antenna for the photoreduction of FAD.
Related Citations:
Crystallization and Preliminary X-Ray Analysis of Cryptochrome 3 from Arabidopsis Thaliana Pokorny, R., Klar, T., Essen, L.-O., Batschauer, A. (2005) Acta Crystallogr Sect F Struct Biol Cryst Commun 61: 935
Organizational Affiliation:
Philipps-Universität Marburg, Department of Chemistry, Hans-Meerwein-Strasse, D-35032 Marburg, Germany.
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