exonuclease VII

{{Infobox protein family

| Symbol = Exonuc_VII_L

| Name = Exonuclease VII, large subunit

| image =

| width =

| caption =

| Pfam = PF02601

| Pfam_clan =

| InterPro = IPR020579

| SMART =

| PROSITE =

| MEROPS =

| SCOP =

| TCDB =

| OPM family =

| OPM protein =

| CAZy =

| CDD =

}}

{{Infobox protein family

| Symbol = Exonuc_VII_S

| Name = Exonuclease VII small subunit

| image = PDB 1vp7 EBI.jpg

| width =

| caption = crystal structure of exodeoxyribonuclease vii small subunit (np_881400.1) from bordetella pertussis at 2.40 a resolution

| Pfam = PF02609

| Pfam_clan =

| InterPro = IPR003761

| SMART =

| PROSITE =

| MEROPS =

| SCOP =

| TCDB =

| OPM family =

| OPM protein =

| CAZy =

| CDD =

}}

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.{{cite journal | title = Ribonuclease VII of Escherichia coli |author1 = Chase, J.W. |author2 =Richardson, C.C. |journal = J. Biol. Chem. |year = 1974 |volume = 249 |pages = 4545–4552 |pmid = 4602029 | issue = 14|doi = 10.1016/S0021-9258(19)42453-8 |doi-access = free }}{{cite journal | title = Exonuclease VII of Escherichia coli |author1 = Chase, J.W. |author2 =Richardson, C.C. |journal = J. Biol. Chem. |year = 1974 |volume = 249 |pages = 4553–4561 |pmid = 4602030 | issue = 14|doi = 10.1016/S0021-9258(19)42454-X |doi-access = free }} It is composed of two nonidentical subunits; one large subunit and 4 small ones.{{cite journal | vauthors = Vales LD, Rabin BA, Chase JW | title = Subunit structure of Escherichia coli exonuclease VII | journal = J. Biol. Chem. | volume = 257 | issue = 15 | pages = 8799–805 |date=August 1982 | doi = 10.1016/S0021-9258(18)34201-7 | pmid = 6284744 | doi-access = free }} 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.

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.{{cite journal |vauthors=Huang SN, Michaels SA, Mitchell BB, Majdalani N, Vanden Broeck A, Canela A, Tse-Dinh YC, Lamour V, Pommier Y |title=Exonuclease VII repairs quinolone-induced damage by resolving DNA gyrase cleavage complexes |journal=Sci Adv |volume=7 |issue=10 |pages= |date=March 2021 |pmid=33658195 |pmc=7929499 |doi=10.1126/sciadv.abe0384 |bibcode=2021SciA....7..384H |url=}} Exonuclease VII participates in repairing such DNA damage by resolving the trapped cleavage complexes.

When Escherichia coli bacteria recA mutants are UV-irradiated, “reckless” DNA degradation occurs that involves exonuclease VII.{{cite journal |vauthors=Repar J, Briški N, Buljubašić M, Zahradka K, Zahradka D |title=Exonuclease VII is involved in "reckless" DNA degradation in UV-irradiated Escherichia coli |journal=Mutat Res |volume=750 |issue=1–2 |pages=96–104 |date=January 2013 |pmid=23123979 |doi=10.1016/j.mrgentox.2012.10.005 |bibcode=2013MRGTE.750...96R |url=}}