oxidized purine nucleobase lesion DNA N-glycosylase activity

Definition

Target type: molecularfunction

Catalysis of the removal of oxidized purine bases by cleaving the N-C1' glycosidic bond between the oxidized purine and the deoxyribose sugar. The reaction involves the formation of a covalent enzyme-substrate intermediate. Release of the enzyme and free base by a beta-elimination or a beta, gamma-elimination mechanism results in the cleavage of the DNA backbone 3' of the apurinic (AP) site. [GOC:elh, PMID:11554296]

Oxidized purine nucleobase lesion DNA N-glycosylase activity is a critical component of the base excision repair (BER) pathway, a major DNA repair mechanism that removes damaged or modified bases from DNA. This activity is responsible for recognizing and excising specific oxidized purine bases, such as 8-oxoguanine (8-oxoG), from the DNA backbone. The enzyme first binds to the damaged base and then cleaves the glycosidic bond between the base and the deoxyribose sugar, releasing the damaged base. This leaves a single-stranded DNA break with a 3'-deoxyribose-5'-phosphate (dRP) residue. The dRP residue is then removed by a separate enzyme, called dRP lyase, and the gap is filled by DNA polymerase and sealed by DNA ligase. The removal of oxidized purine lesions is essential for maintaining the integrity of the genome and preventing mutations, which can lead to cancer and other diseases. The highly specific recognition of oxidized purine lesions by these enzymes is crucial for preventing the accumulation of these lesions, which can lead to genomic instability. These enzymes play a critical role in protecting cells from the harmful effects of oxidative stress.'
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Proteins (5)

Compounds (5)