UV-damaged DNA

Electron donation to nucleobases is a fundamental process exploited by nature to achieve the efficient repair of UV induced lesions in DNA [27, 28]. Nature developed to this end two enzymes, CPD photolyases and (6-4) photolyases, which both inject electrons into the UV damaged DNA bases [29, 30]. Both enzymes are, in many species, including plants, essential for the repair of the UV-light induced DNA lesions depicted in Scheme 1 [31]. 

Pasheva, E.A., Pashev, I.G., and Favre, A. (1998) Preferential binding of high mobility group 1 protein to UV-damaged DNA. Role of the COOH-terminal domain. J. Biol. Chem. 273, 24730-24736. 

Guo Z, Kumagai A, Wang SX, Dunphy WG. Requirement for Atr in phosphorylation of Chkl and cell cycle regulation in response to DNA replication blocks and UV-damaged DNA in Xenopus egg extracts. Genes Dev. 2000 14 2745-2756. 

Figure 1 Reaction mechanism of DNA photolyases (A) mechanism of cyclobutane photolyase and (B) mechanism of (6-4) photolyase. Both photolyases harness blue light energy to remove UV-induced damage and contain two noncovalently bound chromophores. They bind UV-damaged DNA in a reaction that is light independent and carry out catalysis in a light-initiated cyclic electron transfer. In (6-4) photolyase, the (6-4) photoproduct is converted to a four-membered oxetane ring thermally (kT) before the photochemical reaction.

Tang, J. and Chu, G. (2002) Xeroderma pigmentosum complementation group E and UV-damaged DNA binding protein. DNA Repair, 1, 601-616. Groisman, R., Polanowska, J., Kuraoka,... 

Tomato Tomato/RNAi EH DDBl UV-DAMAGED DNA BINDING PROTEIN 1 TF negatively regulates photomorphogenic responses Higher pigment accumulation due to increase in plastid compartment space [82]... 

Mutant loses the ability to repair UV-damaged DNA Mutation in the gene for DNA helicase II. Repair of UV-damaged DNA affected... 

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