Bhattacharjee Ayan, Bowman Gregory R
Departments of Biochemistry & Biophysics and Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, United States.
bioRxiv. 2025 Jun 10:2025.06.07.658438. doi: 10.1101/2025.06.07.658438.
Mechanistic insight into biophysical perturbations caused by pathogenic missense mutations is highly valuable information for the rational design of therapeutics. For hereditary breast and ovarian cancer, multiple pathogenic mutations in the N-terminal domain of have been reported in patients. How exactly these mutations disrupt the catalytic activity of , and thereby lead to oncogenesis, is unknown. Here, we posit that the mechanism of pathogenesis is tied to how binding of activates for E3 ligase activity. We use atomistic molecular dynamics simulations and Markov state modeling to uncover how selects for active conformational states of . We show that the helix bundle, where binds, is allosterically coupled to the E2 interface. Furthermore, we show that selects for conformational states that are pre-organized for E3 activity. Lastly, we show that pathogenic mutations allosterically destabilize active states, whereas hyperactive mutations constitutively increase their likelihood. These results provide a concrete strategy supported by mechanistic insight for the design of restorative small molecules targeting .
深入了解由致病性错义突变引起的生物物理扰动,对于合理设计治疗方法而言是极具价值的信息。对于遗传性乳腺癌和卵巢癌,已有报道称患者的[相关蛋白]N端结构域存在多种致病性突变。这些突变究竟如何破坏[相关蛋白]的催化活性,进而导致肿瘤发生,目前尚不清楚。在此,我们假定发病机制与[相关蛋白]的结合如何激活其E3连接酶活性相关。我们使用原子分子动力学模拟和马尔可夫状态建模来揭示[相关蛋白]如何选择[另一相关蛋白]的活性构象状态。我们表明,[相关蛋白]结合的螺旋束与E2界面存在变构偶联。此外,我们表明[相关蛋白]选择为E3活性预先组织好的构象状态。最后,我们表明致病性突变通过变构作用使活性状态不稳定,而高活性突变则持续增加其可能性。这些结果为设计针对[相关蛋白]的恢复性小分子提供了一种基于机制洞察的具体策略。