Repair polymerase that plays a key role in base-excision repair (PubMed:10556592, PubMed:9207062, PubMed:9572863). During this process, the damaged base is excised by specific DNA glycosylases, the DNA backbone is nicked at the abasic site by an apurinic/apyrimidic (AP) endonuclease, and POLB removes 5′-deoxyribose-phosphate from the preincised AP site acting as a 5′-deoxyribose-phosphate lyase (5′-dRP lyase); through its DNA polymerase activity, it adds one nucleotide to the 3′ end of the arising single-nucleotide gap (PubMed:10556592, PubMed:17526740, PubMed:9556598, PubMed:9572863, PubMed:9614142). Conducts ‘gap-filling’ DNA synthesis in a stepwise distributive fashion rather than in a processive fashion as for other DNA polymerases. It is also able to cleave sugar-phosphate bonds 3′ to an intact AP site, acting as an AP lyase (PubMed:9614142).
