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A new class EC 7, Translocases, has been added to the EC list. It will be part of ENZYME from release 2018_10. Read more about EC 7 here.

ENZYME entry: EC 4.1.99.13

Accepted Name

(6-4)DNA photolyase.

Alternative Name(s)

DNA photolyase.

Reaction catalysed

(6-4) photoproduct (in DNA) <=> 2 pyrimidine residues (in DNA)

Cofactor(s)

FAD.

Comment(s)

The overall repair reaction consists of two distinct steps, one of which is light-independent and the other one light-dependent.
In the initial light-independent step, a 6-iminium ion is thought to be generated via proton transfer induced by two histidines highly conserved among the (6-4) photolyases.
This intermediate spontaneously rearranges to form an oxetane intermediate by intramolecular nucleophilic attack.
In the subsequent light-driven reaction, one electron is believed to be transferred from the fully reduced FAD cofactor (FADH(-)) to the oxetane intermediate thus forming a neutral FADH radical and an anionic oxetane radical, which spontaneously fractures.
The excess electron is then back-transferred to the flavin radical restoring the fully reduced flavin cofactor and a pair of pyrimidine bases.

Cross-references

PROSITE

BRENDA

EC2PDB

ExplorEnz

PRIAM enzyme-specific profiles

KEGG Ligand Database for Enzyme Nomenclature

IUBMB Enzyme Nomenclature

IntEnz

MEDLINE

MetaCyc

UniProtKB/Swiss-Prot

A9CH39, PHRB_AGRFC;

O48652, UVR3_ARATH;

Q0E2Y1, UVR3_ORYSJ;

All UniProtKB/Swiss-Prot entries referenced in this entry, with possibility to download in different formats, align etc.

All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 4.1.99.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 4.1.-.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 4.-.-.-