Homologous Superfamily

Exonuclease, phage-type/RecB, C-terminal (IPR011604)

Short name: Exonuc_phg/RecB_C

Overlapping entries


This superfamily represents phage-type exonucleases (EC: and the C-terminal domain of RecB exodeoxyribonuclease V exonuclease (EC:, which are closely related in sequence and structure, containing a restriction enzyme-like core fold.

Exonuclease from Bacteriophage lambda facilitates phage DNA recombination through the double-strand break repair (DSBR) and single-strand annealing pathways; it is also important for the late, rolling-circle mode of lambda DNA replication. This magnesium-dependent enzyme catalyses the exonucleolytic cleavage of DNA in the 5'- to 3'-direction to yield nucleoside 5'-phosphates. Lambda exonuclease is a trimer of three subunits that form a toroid structure with a tapered channel passing through the middle [PMID: 9295273].

Exodeoxyribonuclease V, or RecBCD holoenzyme, is a multifunctional nuclease with potent ATP-dependent exodeoxyribonuclease activity. Ejection of RecD, as occurs at chi recombinational hotspots, cripples exonuclease activity in favor of recombinagenic helicase activity. All proteins in this family for which functions are known are DNA-DNA helicases that are used as part of an exonuclease-helicase complex (made up of RecBCD homologues) that function to generate substrates for the initiation of recombination and recombinational repair. The complex catalyses exonucleolytic cleavage in either the 5' to 3' or 3' to 5' direction to yield 5-phosphooligonucleotides in the presence of ATP [PMID: 15538360].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.