"Asclepius" C#6

When the DNA sequence for cryptochrome 1 was obtained, it was found that there was significant homology to another class of light-absorbing protein, the DNA photolyases involved in DNA repair and the process of photoreactivation. Photolyases are DNA repair enzymes that repair damage caused by exposure to ultraviolet light. These enzymes require visible light both for their own activation and for the actual DNA repair. The DNA repair mechanism involving photolyases is called photoreactivation. Enzymes are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. UVR8 has been found to mediate UV-B-induced photomorphogenesis including modulation of biosynthetic pathways, photosynthetic performance, morphogenesis, and responses to pathogens principally in mature light-grown plants. Given that studies of DNA repair have now provided ample evidence that there are signal transduction pathways activated by DNA lesions, it is not unreasonable to consider DNA itself as a possible photoreceptor. In just a few seconds, ultraviolet light from the sun can damage DNA by creating hundreds of unwanted links within DNA's double helix. These modifications make the genetic material bulky and unreadable by DNA replication tools, leading to permanent mutations that can cause cancer and other diseases if left unrepaired. Photolyases belong to the cryptochrome/photolyase protein family (CPF) which perform different functions such as DNA repair, circadian photoreceptor, and transcriptional regulation. Photolyase is a flavoprotein that repairs UV-induced DNA damages of cyclobutane pyrimidine dimer (CPD) and pyrimidine-pyrimidone (6-4) photoproducts using blue-light as an energy source. This enzyme has two chromophores: flavin adenine dinucleotide (FAD) as a cofactor and a photo antenna such as methyltetrahydrofolate (MTHF). The FAD is essential for catalysis of the DNA repair. The second chromophore absorbs photons from the blue light spectrum and transfers energy to FAD to increase the repair efficiency of the enzyme. UV-B resistance 8 (UVR8) also known as ultraviolet-B receptor UVR8 is a UV-B – sensing protein found in plants and possibly other sources. It is responsible for sensing ultraviolet light in the range 280-315 nm and initiating the plant stress response. 90+% activated at 285nm