Structure and function of DNA photolyase and cryptochrome blue-light photoreceptors

Photolyases are monomeric proteins of 450-550 amino acids and two noncovalently bound chromophore cofactors. One of the cofactors is always FAD, and the second is either MTHF or 8-HDF. The FAD is the essential cofactor, while the second chromophore (MTHF or 8-HDF) is not always necessary. However, under limiting light the second chromophore may increase the rate of repair 10-100-fold depending on the wavelength used to effect catalysis. The current knowledge on the structure of the enzyme is summarized. Furthermore, the reaction mechanism of repair and repair-related phenomena is analyzed.