class II DNA-(apurinic or apyrimidinic site) endonuclease activity

Definition

Target type: molecularfunction

Catalysis of the hydrolysis of ester linkages immediately 5' to an apurinic/apyrimidinic (AP; also called abasic) site within a deoxyribonucleic acid molecule by creating internal breaks, generating a single-strand break with 5'-deoxyribose phosphate and 3'-hydroxyl ends. [PMID:19401441]

Class II DNA-(apurinic or apyrimidinic site) endonucleases are a family of enzymes that play a crucial role in DNA repair pathways. They specifically recognize and cleave DNA at abasic sites, also known as AP sites, which are lesions in the DNA backbone where a purine or pyrimidine base has been lost. These sites can arise from spontaneous hydrolytic DNA damage or from the action of other DNA repair enzymes. The enzymatic activity of class II DNA-(apurinic or apyrimidinic site) endonucleases is critical for removing these lesions and preventing the accumulation of DNA damage, which can lead to mutations, cell death, and cancer.

The mechanism of action of class II DNA-(apurinic or apyrimidinic site) endonucleases involves the recognition and binding to the abasic site in the DNA. This recognition is often facilitated by a conserved active site motif known as the "helix-hairpin-helix" motif. Once bound, the enzyme catalyzes the hydrolysis of the phosphodiester bond 5' to the abasic site, resulting in a single-stranded break in the DNA. This nick in the DNA allows other repair enzymes to access the damaged region and initiate the repair process.

Class II DNA-(apurinic or apyrimidinic site) endonucleases are found in all living organisms, from bacteria to humans, highlighting their essential role in maintaining genome integrity. They are involved in various DNA repair pathways, including base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR). Dysregulation of class II DNA-(apurinic or apyrimidinic site) endonuclease activity has been linked to various diseases, including cancer and neurodegenerative disorders.'
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Proteins (1)

Compounds (17)