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DNA photolyase is an evolutionary conserved protein domain. This domain binds a light harvesting cofactor. Deoxyribodipyrimidine photolyase (DNA photolyase) is a DNA repair enzyme. It binds to UV-damaged DNA containing pyrimidine dimers and, upon absorbing a near-UV photon (300 to 500 nm), breaks the cyclobutane ring joining the two pyrimidines of the dimer. DNA photolyase is an enzyme that requires two chromophore-cofactors for its activity: a reduced FADH2 and either 5,10-methenyltetrahydrofolate (5,10-MTFH) or an oxidized 8-hydroxy-5-deazaflavin (8-HDF) derivative (F420). The folate or deazaflavin chromophore appears to function as an antenna, while the FADH2 chromophore is thought to be responsible for electron transfer. On the basis of sequence similarities DNA photolyases can be grouped into two classes. The first class contains enzymes from Gram-negative and Gram-positive bacteria, the halophilic archaebacteria Halobacterium halobium, fungi and plants. Class 1 enzymes bind either 5,10-MTHF (''E. coli'', fungi, etc.) or 8-HDF (''S. griseus'', ''H. halobium''). Proteins containing this domain also include ''Arabidopsis thaliana'' cryptochromes 1 (CRY1) and 2 (CRY2), which are blue light photoreceptors that mediate blue light-induced gene expression. == Examples == Human proteins containing this domain include: * CRY1 * CRY2 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「DNA photolyase (protein domain)」の詳細全文を読む スポンサード リンク
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