碱基切除修复(BER)是通过修复DNA损伤来维持基因组稳定性的重要系统之一。BER是涉及多种酶的多步骤过程,包括损伤特异性DNA糖基化酶,无嘌呤/无嘧啶(AP)核酸内切酶1,DNA聚合酶β,和DNA连接酶.通过BER参与者之间的多种蛋白质-蛋白质相互作用来实现BER的协调。尽管如此,这些相互作用的机制及其在BER协调中的作用知之甚少。这里,我们报告了在各种DNA糖基化酶(AAG,OGG1,NTHL1,MBD4,UNG,或SMUG1)使用快速淬灭流和停流荧光方法。已显示,在有或没有5'-dRP模拟基团的情况下,Polβ有效地将单个核苷酸添加到不同类型的单链断裂中。获得的数据表明,DNA糖基化酶AAG,OGG1,NTHL1,MBD4,UNG,和SMUG1,而不是NEIL1,增强Polβ对模型DNA中间体的活性。
Base excision repair (BER) is one of the important systems for the maintenance of genome stability via repair of DNA lesions. BER is a multistep process involving a number of enzymes, including damage-specific DNA glycosylases, apurinic/apyrimidinic (AP) endonuclease 1, DNA polymerase β, and DNA ligase. Coordination of BER is implemented by multiple protein-protein interactions between BER participants. Nonetheless, mechanisms of these interactions and their roles in the BER coordination are poorly understood. Here, we report a study on Polβ\'s nucleotidyl transferase activity toward different DNA substrates (that mimic DNA intermediates arising during BER) in the presence of various DNA glycosylases (AAG, OGG1, NTHL1, MBD4, UNG, or SMUG1) using rapid-quench-flow and stopped-flow fluorescence approaches. It was shown that Polβ efficiently adds a single nucleotide into different types of single-strand breaks either with or without a 5\'-dRP-mimicking group. The obtained data indicate that DNA glycosylases AAG, OGG1, NTHL1, MBD4, UNG, and SMUG1, but not NEIL1, enhance Polβ\'s activity toward the model DNA intermediates.