Photo-Induced DNA-Damage and Its Repair

Pyrimidine base, thymine 5 present in DNA, on exposure to UV light undergoes dimerization to give 6 and 7 by [2+2]-cycloaddition reaction [8]. 

Due to this dimerization, this dimeric thymine alters the structure of DNA and consequently inhibits replication of DNA. Such mutation of DNA results in cell death in some instances. Repairing of this mutation may be done by exposing the DNA at longer wavelength ( 300 nm) of light [9]. 

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