屏障自编码因子（Banf1）是一种小型DNA桥蛋白。Banf1与DNA的结合状态由其N端的磷酸化和脱磷酸化调节，这在细胞增殖中起着关键作用。Banf1可在Ser4位点磷酸化为单磷酸化的Banf1，进一步在Thr3位点磷酸化形成双磷酸化的Banf1。几十年前观察到单磷酸化的Banf1不能与DNA结合。然而，其潜在的分子和原子水平机制仍然不清楚。对这些机制的清晰理解将有助于干预细胞增殖过程，以改善全球健康。在本文中，我们使用全面和系统的分子建模和分子动力学模拟，探讨了未磷酸化的Banf1与DNA结合的详细原子基础，以及单磷酸化和双磷酸化Banf1如何削弱这些原子基础以消除其与DNA的结合能力，并进一步探索了单磷酸化和双磷酸化Banf1的DNA结合能力。这项工作详细呈现了Banf1与DNA之间残基级别的结合能、氢键和水桥，其中一些尚未报道。此外，我们揭示了单磷酸化Banf1导致其N端二级结构的变化，进而引起Banf1的DNA结合表面的显著变化，从而消除了其对DNA的结合能力。在原子级别上，我们还发现了与单磷酸化相关的相互作用的改变，导致Banf1 N端二级结构的变化。此外，我们的建模结果显示，磷酸化Banf1具有占优势的N端二级结构与DNA的结合亲和力显著降低，并且在分子动力学模拟中其绑定姿态不稳定。这些发现有助于未来研究预测Banf1突变对其与DNA结合能力的影响，并为通过引起Banf1 N端结构变化来靶向细胞增殖的治疗方法（如抗癌药物）开辟了新的途径。

Barrier-to-autointegration factor (Banf1) is a small DNA-bridging protein. The binding status of Banf1 to DNA is regulated by its N-terminal phosphorylation and dephosphorylation, which plays a critical role in cell proliferation. Banf1 can be phosphorylated at Ser4 into mono-phosphorylated Banf1, which is further phosphorylated at Thr3 to form di-phosphorylated Banf1. It was observed decades ago that mono-phosphorylated Banf1 cannot bind to DNA. However, the underlying molecular- and atomic-level mechanisms remain unclear. A clear understanding of these mechanisms will aid in interfering with the cell proliferation process for better global health. Herein, we explored the detailed atomic bases of unphosphorylated Banf1-DNA binding and how mono- and di-phosphorylation of Banf1 impair these atomic bases to eliminate its DNA-binding capability, followed by exploring the DNA-binding capability of mono- and di-phosphorylation Banf1, using comprehensive and systematic molecular modelling and molecular dynamics simulations. This work presented in detail the residue-level binding energies, hydrogen bonds and water bridges between Banf1 and DNA, some of which have not been reported. Moreover, we revealed that mono-phosphorylation of Banf1 causes its N-terminal secondary structure changes, which in turn induce significant changes in Banf1's DNA binding surface, thus eliminating its DNA-binding capability. At the atomic level, we also uncovered the alterations in interactions due to the induction of mono-phosphorylation that result in the N-terminal secondary structure changes of Banf1. Additionally, our modelling showed that phosphorylated Banf1 with their dominant N-terminal secondary structures bind to DNA with a significantly lower affinity and the docked binding pose are not stable in MD simulations. These findings help future studies in predicting effect of mutations in Banf1 on its DNA-binding capability and open a novel avenue for the development of therapeutics such as cancer drugs, targeting cell proliferation by inducing conformational changes in Banf1's N-terminal domain.