Among human four Y-family DNA polymerases, hPol ι is exceptionally error-prone in DNA synthesis. 6 mA plays significant roles in epigenetic regulation of numerous biological processes. Nonetheless, its effects on DNA replication by hPol ι is still unclear. In this work, we found that 6 mA and Hyp, the intermediate of 6 mA, inhibited the replication of DNA by hPol ι. 6 mA lost priority in extension beyond 6 mA:T pair, partially reducing dTTP incorporation efficiency and inhibiting next-base extension. Hyp was prone to dCTP incorporation and extension beyond Hyp:C instead of Hyp:T pair. Statistically, 6 mA primarily reduced the burst incorporation rate (kpol) and slightly increased the dissociation constant (Kd,dTTP). However, Hyp mainly increased the Kd,dCTP yet did not affect the kpol, both reducing the burst incorporation efficiency (kpol/Kd,dCTP). 6 mA together with Hyp weakened the binding affinity of hPol ι to DNA in binary or ternary complex. The misincorporation opposite 6 mA or Hyp further weakened this binding affinity. The methyl group in 6 mA doesn't almost affect the H-bond formation with dTTP, therefore mildly inhibiting dTTP incorporation. As an analogue of G, Hyp can form only two H-bonds with dCTP, thus reducing dCTP incorporation. This work provides a new insight in how the epigenetically modified 6 mA and its intermediate Hyp affect replication of DNA by human DNA polymerase ι.

中文翻译：

---

表观遗传修饰的N6-甲基腺嘌呤通过人DNA聚合酶iota抑制DNA复制。

在人的四个Y家族DNA聚合酶中，hPol 1在DNA合成中特别容易出错。6 mA在众多生物学过程的表观遗传调控中起着重要作用。尽管如此，其对hPO1的DNA复制的影响仍不清楚。在这项工作中，我们发现6mA和6mA的中间产物Hyp抑制了hPol 1的DNA复制。6 mA在扩展超过6 mA：T对时失去优先级，部分降低了dTTP整合效率并抑制了下碱基扩展。Hyp倾向于dCTP掺入和扩展，而不是Hyp：C，而不是Hyp：T对。从统计上讲，6 mA主要降低了猝发掺入率（kpol），并略微提高了解离常数（Kd，dTTP）。但是，Hyp主要增加了Kd，dCTP，但并未影响kpol，但都降低了突发合并效率（kpol / Kd，dCTP）。6mA与Hyp一起减弱了hPol 1对二元或三元复合物中的DNA的结合亲和力。与6 mA或Hyp相反的错误掺入进一步削弱了这种结合亲和力。6 mA中的甲基几乎不会影响dTTP的氢键形成，因此会轻微抑制dTTP的掺入。作为G的类似物，Hyp只能与dCTP形成两个H键，从而减少了dCTP的掺入。这项工作为表观遗传修饰的6 mA及其中间Hyp如何影响人DNA聚合酶1的DNA复制提供了新的见识。因此，可适度抑制dTTP的掺入。作为G的类似物，Hyp只能与dCTP形成两个H键，从而减少了dCTP的掺入。这项工作为表观遗传修饰的6 mA及其中间Hyp如何影响人DNA聚合酶1的DNA复制提供了新的见识。因此，可适度抑制dTTP的掺入。作为G的类似物，Hyp只能与dCTP形成两个H键，从而减少了dCTP的掺入。这项工作为表观遗传修饰的6 mA及其中间Hyp如何影响人DNA聚合酶1的DNA复制提供了新的见识。