CATH Classification

Domain Context

CATH Clusters

Superfamily Deoxyribodipyrimidine photolyase-related
Functional Family (6-4) photolyase

Enzyme Information
(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)

Agrobacterium fabrum str. C58
(6-4) photolyase

PDB Structure

External Links
Primary Citation
Crystal Structures of Bacterial (6-4) Photolyase Mutants with Impaired DNA Repair Activity.
Zhang, F., Ma, H., Bowatte, K., Kwiatkowski, D., Mittmann, E., Qasem, H., Krau, N., Zeng, X., Ren, Z., Scheerer, P., Yang, X., Lamparter, T.
Photochem. Photobiol.