AP endonuclease 1 has no biologically significant 3(')-->5(')-exonuclease activity |
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Authors: | Lebedeva Natalia A Khodyreva Svetlana N Favre Alain Lavrik Olga I |
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Institution: | Novosibirsk Institute of Bioorganic Chemistry, Siberian Division of Russian Academy of Sciences, Prospect Lavrentiev 8, 630090, Novosibirsk, Siberia, Russia. |
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Abstract: | The 3(')-->5(')-exonucleolytic activity of human apurinic/apyrimidinic endonuclease 1 (APE1) on mispaired DNA at the 3(')-termini of recessed, nicked or gapped DNA molecules was analyzed and compared with the primary endonucleolytic activity. We found that under reaction conditions optimal for AP endonuclease activity the 3(')-->5(')-exonuclease activity of APE1 manifests only at enzyme concentration elevated by 6-7 orders of magnitude. This activity does not show a preference to mismatched compared to matched DNA structures as well as to nicked or gapped DNA substrates in comparison to recessed ones. Therefore, the 3(')-->5(')-exonuclease activity associated with APE1 can hardly be considered as key mechanism that improves fidelity of DNA repair. |
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Keywords: | Apurinic/apyrimidinic endonuclease Base excision repair 3′→5′-exonuclease activity |
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