Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Deoxyadenosine undergoes spontaneous deamination to deoxyinosine in DNA. Based on amino acids sequence homology, putative homologs of endonuclease V were identified in several organisms including archaebacteria, eubacteria as well as eukaryotes. The translated amino acid sequence of the Archaeoglobus fulgidus nfi gene shows 39% identity and 55% similarity to the E. coli nfi gene. A. fulgidus endonuclease V was cloned and expressed in E. coli as a C-terminal hexa-histidine fusion protein. The C-terminal fusion protein was purified to apparent homogeneity by a combination of Ni(++) affinity and MonoS cation exchange liquid chromatography. The purified C-terminal fusion protein has a molecular weight of about 25kDa and showed endonuclease activity towards DNA containing deoxyinosine. A. fulgidus endonuclease V has an absolute requirement for Mg(2+) and an optimum reaction temperature at 85 degrees C. However, in contrast to E. coli endonuclease V, which has a wide substrate spectrum, endonuclease V from A. fulgidus recognized only deoxyinosine. These data suggest that the deoxyinosine cleavage activity is a primordial activity of endonuclease V and that multiple enzymatic activities of E. coli endonuclease V were acquired later during evolution.
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PMID:A deoxyinosine specific endonuclease from hyperthermophile, Archaeoglobus fulgidus: a homolog of Escherichia coli endonuclease V. 1105 88

Abasic lesions are unable to form Watson-Crick hydrogen bonds with nucleotides. Nonetheless, polymerase and repair enzymes distinguish between various oxidized abasic lesions, as well as from nonoxidized abasic sites (AP). The C2-AP lesion is produced when DNA is exposed to gamma-radiolysis. Its effects on polymerases and repair enzymes are unknown. A recently reported method for the chemical synthesis of oligonucleotides containing C2-AP at a defined site was utilized for studying the activity of Klenow exo(-) and repair enzymes on templates containing the lesion. The C2-AP lesion has a similar effect on Klenow exo(-) as do AP and C4-AP sites. Deoxyadenosine is preferentially incorporated opposite C2-AP, but extension of the primer past the lesion is strongly blocked. C2-AP is incised less efficiently by exonuclease III and endonuclease IV than are other abasic lesions. Furthermore, although a Schiff base between C2-AP and endonuclease III can be chemically trapped, the location of the 3'-phosphate alpha with respect to the aldehyde prevents beta-elimination associated with the lyase activity of type I base excision repair enzymes. The interactions of the C2'-oxidized abasic site with Klenow exo(-) and repair enzymes suggest that the lesion will be mutagenic and that it will be removed by strand displacement synthesis and flap endonuclease processing via a long patch repair mechanism.
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PMID:In vitro replication and repair of DNA containing a C2'-oxidized abasic site. 1556 14