AP2EcAP endonuclease family 2 |
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| SMART accession number: | SM00518
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| Description: |
These endonucleases play a role in DNA repair. Cleave phosphodiester bonds at apurinic or apyrimidinic sites |
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| Interpro abstract (IPR001719): |
Cellular DNA is spontaneously and continuously damaged by environmental and internal factors such as X-rays, UV light and agents such as the antitumor drugs bleomycin and neocarzinostatin or those that generate oxygen radicals. Apurinic/apyrimidinic (AP) sites can form spontaneously or as highly cytotoxic intermediates in the removal of the damaged base by the base excision repair (BER) pathway. DNA repair at the AP sites is initiated by specific endonuclease cleavage of the phosphodiester backbone. Such endonucleases are also generally capable of removing blocking groups from the 3'terminus of DNA strand breaks. AP endonucleases can be classified into two families based on sequence similarity. Family 2 groups the enzymes listed below [(PUBMED:1693433), (PUBMED:7661852)]. APN1 and endonuclease IV have been shown to be transition metalloproteins that bind three zinc ions [(PUBMED:1720775), (PUBMED:10458614)]. The metal-binding sites have been determined from the 3D-structure of Escherichia coli endonuclease IV [(PUBMED:10458614), (PUBMED:17242363), (PUBMED:18408731)], which shows an alpha/beta-barrel fold similar to that of other divalent metal-dependent TIM barrel enzymes, such as xylose isomerase.
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| GO process: | DNA repair (GO:0006281) |
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| GO component: | intracellular (GO:0005622) |
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| GO function: | DNA binding (GO:0003677), zinc ion binding (GO:0008270) |
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| Family alignment: |
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There are 897
AP2Ec domains in 897 proteins in SMART's nrdb database.
Click on the following links for more information.
- Evolution (species in which this domain is found)
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- Literature (relevant references for this domain)
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Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.
- Levin JD, Shapiro R, Demple B
- Metalloenzymes in DNA repair. Escherichia coli endonuclease IV and Saccharomyces cerevisiae Apn1.
- J Biol Chem. 1991; 266: 22893-8
- Display abstract
Escherichia coli endonuclease IV and its Saccharomyces cerevisiae homologue Apn1, two DNA repair enzymes for free radical damages, were previously shown to be inactivated by metal-chelating agents. In the present study, atomic absorption spectrometry of endonuclease IV revealed the presence of 2.4 zinc and 0.7 manganese atoms, whereas Apn1 contained 3.3 zinc atoms and no significant manganese. EDTA-inactivated endonuclease IV retained 0.7 zinc atom but little detectable manganese. ZnCl2 reactivated 1,10-phenanthroline-treated Apn1, but was ineffective with endonuclease IV treated with either 1,10-phenanthroline or EDTA. In contrast, enzymatic activity was restored to both enzymes after EDTA treatment by incubation with CoCl2 and to a lesser extent by MnCl2. Endonuclease IV, reactivated with CoCl2 or MnCl2, regained all of the activities characteristic of the native enzyme. MnCl2 was as effective as CoCl2 at restoring activity to the 1,10-phenanthroline-treated enzymes. The results indicate that intrinsic metals play critical roles in both endonuclease IV and Apn1 and that manganese may perform a special function in endonuclease IV. Possible mechanistic roles for the metals in these DNA repair enzymes are discussed.
- Structure (3D structures containing this domain)
3D Structures of AP2Ec domains in PDB
| PDB code | Main view | Title | | 1qtw |  | High-resolution crystal structure of the escherichia coli dna repair enzyme endonuclease iv |
| 1qum |  | Crystal structure of escherichia coli endonuclease iv in complex with damaged dna |
| 1xp3 |  | Crystal structure of endonuclease iv (ba4508) from bacillus anthracis at 2.57a resolution. |
| 2nq9 |  | High resolution crystal structure of escherichia coli endonuclease iv (endo iv) y72a mutant bound to damaged dna |
| 2nqh |  | High resolution crystal structure of escherichia coli endonuclease iv (endo iv) e261q mutant |
| 2nqj |  | Crystal structure of escherichia coli endonuclease iv (endo iv) e261q mutant bound to damaged dna |
- Links (links to other resources describing this domain)
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