ID   4.1.99.13
DE   (6-4)DNA photolyase.
AN   DNA photolyase.
CA   (6-4) photoproduct (in DNA) = 2 pyrimidine residues (in DNA).
CC   -!- The overall repair reaction consists of two distinct steps, one of
CC       which is light-independent and the other one light-dependent.
CC   -!- In the initial light-independent step, a 6-iminium ion is thought to
CC       be generated via proton transfer induced by two histidines highly
CC       conserved among the (6-4) photolyases.
CC   -!- This intermediate spontaneously rearranges to form an oxetane
CC       intermediate by intramolecular nucleophilic attack.
CC   -!- In the subsequent light-driven reaction, one electron is believed to
CC       be transferred from the fully reduced FAD cofactor (FADH(-)) to the
CC       oxetane intermediate thus forming a neutral FADH radical and an
CC       anionic oxetane radical, which spontaneously fractures.
CC   -!- The excess electron is then back-transferred to the flavin radical
CC       restoring the fully reduced flavin cofactor and a pair of pyrimidine
CC       bases.
DR   A9CH39, PHRB_AGRFC ;  O48652, UVR3_ARATH ;  Q0E2Y1, UVR3_ORYSJ ;
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