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DNA Photolyase and the Role of Flavin in DNA Repair
Book chapter

DNA Photolyase and the Role of Flavin in DNA Repair

Marilyn Schuman Jorns
Chemistry and Biochemistry of Flavoenzymes, pp 317-335
1991
DOI: https://doi.org/10.1201/9781351070577-13

Abstract

Action Spectrum Isolated Enzyme Cyclobutane Dimers Aprotic Dipolar Solvents Quantum Yield Agmenellum Quadruplicatum Flavin Radical Thymine Dimer Spectral Properties Mol Enzyme Pterin Derivative Dimer Radical Cation Streptomyces Griseus Absorption Spectrum Free Chromophore Coenzyme F420 Thymine Dimer Formation Exhibit Absorption Maxima Emission Bands Dimer Radical American Chemical Society Cyanobacteria Anacystis Nidulans Covalent Adduct Enzyme Substrate Complex Assay Buffer
Exposure of DNA to ultraviolet light results in the formation of cyclobutane dimers between adjacent pyrimidine residues. Since direct excitation of pyrimidine dimers cannot occur with visible light, it was long suspected that the photolyase reaction might be a photosensitized process involving one or more enzyme-bound chromophores that absorbed visible light. Highly purified photolyase has been isolated from Escherichia coli, Saccharomyces cerevisiae, Streptomyces griseus, the green alga Scenedesmus acutus, and the cyanobacteria Anacystis nidulans. Plasmids which overproduce photolyase have been constructed for the enzymes from E. coli and yeast. Several factors indicate that the binding of E. coli photolyase to dimers in DNA involves interaction of the enzyme with a limited region immediately surrounding the dimer. The identification of 8-hydroxy-5-deazaflavin in Scenedesmus acutus photolyase is the direct evidence for the presence of the chromophore in eukaryotes. The chromophores in S. acutus photolyase are released as a nearly equimolar mixture of oxidized flavin adenine dinucleotide plus an 8-hydroxy-5-deazaflavin derivative.

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