LIG3-mediated DNA ligation via the single-nucleotide replacement pathway

After POLB (DNA polymerase beta) fills a single nucleotide gap created by the APEX1 and POLB-mediated excision of the apurinic/apyrimidinic (AP) site in the damaged DNA strand, LIG3 (DNA ligase 3), recruited to POLB-bound AP site by XRCC1, ligates the two DNA strand fragments, thus completing the base excision repair (Kubota et al. 1996).

在POLB（DNA聚合酶β）填充由APEX1和POLB介导的嘌呤/嘧啶二酮（AP）位点损伤DNA链中形成的单个核苷酸间隙之后，LIG3（DNA连接酶3）被XRCC1招募至与POLB结合的AP位点，从而连接两个DNA链片段，完成基础切除修复过程（Kubota等，1996年）。