| Type: | Domain | Name: | DNA photolyase, N-terminal |
| Description: | The photolyase/cryptochrome family consists of flavoproteins that perform various functions using blue-light photons as an energie source. It is presentin all three domains of life, that is, archaea, eubacteria, and eukaryotes, and hence has arisen very early during evolution to protect genomes againstthe genotoxic effects of ultraviolet light originating from the sun. The photolyase/cryptochrome family is divided into two major groups: photolyasesand cryptochromes. Photolyases repair cytotoxic and mutagenic UV-induced photolesions in DNA in many species frombacteria to plants and animals by using a light-dependent repair mechanism. It involves light absorption, electron transfer from an excited reduced anddeprotanated FADH(-) to the flipped-out photolesion, followed by the fragmentation of the photolesions. Cryptochromes are highly related proteinsthat generally no longer repair damaged DNA, but function as photoreceptors. Cryptochromes regulate growth and development in plants and the circadianclock in animals [, , , , , , ].Both photolyases and cryptochromes have a bilobal architecture consisting of two domains: an N-terminal alpha/beta domain that may contain a light-harvesting chromophore to additionally broaden their activity spectra and a C- terminal alpha-helical catalytic domain comprising the light-sensitive FADcofactor. Diverse classes of antenna chromophores likes 5,10- methenyltetrahydrofolate (MTHF), 8-hydroxydeazaflavin, FMN or FAD have beenidentified in some photolyase/cryptochrome to broaden their activity spectra, whereas many others apparently lack any bound antenna chromophores.This entry represents the photolyase/cryptochrome alpha/beta domain. It adopts a dinucleotide binding fold with a five-stranded parallel beta sheet flanked on both sides by alpha helices [, ]. | Short Name: | DNA_photolyase_N |
