Spore photoproduct lyase (EC 188.8.131.52, SAM, SP lyase, SPL, SplB, SplG) is a radical SAM enzyme that repairs lesions that arise upon UV-radiation of bacterial DNA. These lesions include cross linking at bipyrimidine sites between strands of DNA; this cross linking alters DNA structure and inhibits DNA replication. 
The repair mechanism utilizing spore photoproduct lyase is one of the reasons for the resilience of certain bacterial spores. Through a series of radical reactions the photodimer, 3 5-thyminyl-5,6-dihydrothymine, is disconnected to give back two functional thymine rings.
Spore photoproduct lyase is part of one of two main pathways which are used to repair cross linked 5-thyminyl-5,6-dihydrothymine caused by UV radiation: the spore-specific DNA repair system (which utilizes spore photoproduct lyase), and the general nucleotide excision repair pathway (NER). 
|Spore photoproduct lyase|
|PDB structures||RCSB PDB PDBe PDBsum|