AP位点修复通过单核苷酸替换途径
中文名称
通路描述
单核苷酸替换途径的碱基切除修复似乎有助于修复大多数受损碱基。在DNA糖基化酶介导的受损碱基切割后，内切酶APEX1被招募到损伤部位，它切割缺失脱氧核糖残基的5'侧。DNA聚合酶β（POLB）随后切割AP糖磷酸基团的3'侧，从而切除AP残基。APEX1随后被释放，XRCC1:LIG3复合物被招募，POLB介导替换残基的合成。在LIG3介导的替换残基连接后，XRCC1:LIG3复合物从DNA上解离（Lindahl and Wood, 1999）。当末端糖磷酸基团的构象使得其无法被POLB的AP裂解活性切割时，会采用另一种BER途径。
英文描述
Resolution of AP sites via the single-nucleotide replacement pathway The single nucleotide replacement pathway of base excision repair appears to facilitate the repair of most damaged bases. Following DNA glycosylase mediated cleavage of the damaged base, the endonuclease APEX1 is recruited to the site of damage where it cleaves the 5' side of the abasic (AP) deoxyribose residue. DNA polymerase beta (POLB) then cleaves the 3' side of the AP sugar phosphate, thus excising the AP residue. APEX1 is subsequently released, the XRCC1:LIG3 complex is recruited, and POLB mediates the synthesis of the replacement residue. Following LIG3 mediated ligation of the replaced residue, the XRCC1:LIG3 complex dissociates from DNA (Lindahl and Wood, 1999). An alternative BER pathway is employed when the structure of the terminal sugar phosphate is such that it cannot be cleaved by the AP lyase activity of POLB.
所含基因
3 个基因