CATH Classification

Domain Context

CATH Clusters

Superfamily DNA Cyclobutane Dipyrimidine Photolyase, subunit A, domain 3
Functional Family (6-4) photolyase

Enzyme Information

4.1.99.13
(6-4)DNA photolyase.
based on mapping to UniProt A9CH39
(6-4) photoproduct (in DNA) = 2 pyrimidine residues (in DNA).
-!- 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.

UniProtKB Entries (1)

A9CH39
PHRB_AGRFC
Agrobacterium fabrum str. C58
(6-4) photolyase

PDB Structure

PDB 4DJA
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Crystal structure of a prokaryotic (6-4) photolyase with an Fe-S cluster and a 6,7-dimethyl-8-ribityllumazine antenna chromophore.
Zhang, F., Scheerer, P., Oberpichler, I., Lamparter, T., Krauss, N.
Proc.Natl.Acad.Sci.USA