Exonuclease VII

The enzyme exodeoxyribonuclease VII (EC 3.1.11.6, Escherichia coli exonuclease VII, E. coli exonuclease VII, endodeoxyribonuclease VII, exodeoxyribonuclease VII) is a bacterial exonuclease enzyme.^[1][2] It is composed of two nonidentical subunits; one large subunit and 4 small ones.^[3] that catalyses exonucleolytic cleavage in either 5′- to 3′- or 3′- to 5′-direction to yield nucleoside 5′-phosphates. The large subunit also contains an N-terminal OB-fold domain that binds to nucleic acids.

Exonuclease VII, large subunit
Identifiers
Symbol	Exonuc_VII_L
Pfam	PF02601
InterPro	IPR020579
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Exonuclease VII small subunit
crystal structure of exodeoxyribonuclease vii small subunit (np_881400.1) from bordetella pertussis at 2.40 a resolution
Identifiers
Symbol	Exonuc_VII_S
Pfam	PF02609
InterPro	IPR003761
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

The widely used quinolone antibiotics induce DNA damage in bacterial cells by trapping DNA gyrase (an essential type II topoisomerase), leading to blocked gyrase cleavage complexes.^[4] Exonuclease VII participates in repairing such DNA damage by resolving the trapped cleavage complexes.^[4]

When Escherichia coli bacteria recA mutants are UV-irradiated, “reckless” DNA degradation occurs that involves exonuclease VII.^[5]