Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada.
CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research Centre, Institute of Cancer Research, London SW3 6JB, UK.
Mol Cell. 2022 Aug 18;82(16):2939-2951.e5. doi: 10.1016/j.molcel.2022.06.011. Epub 2022 Jul 5.
PARP1 rapidly detects DNA strand break damage and allosterically signals break detection to the PARP1 catalytic domain to activate poly(ADP-ribose) production from NAD. PARP1 activation is characterized by dynamic changes in the structure of a regulatory helical domain (HD); yet, there are limited insights into the specific contributions that the HD makes to PARP1 allostery. Here, we have determined crystal structures of PARP1 in isolated active states that display specific HD conformations. These captured snapshots and biochemical analysis illustrate HD contributions to PARP1 multi-domain and high-affinity interaction with DNA damage, provide novel insights into the mechanics of PARP1 allostery, and indicate how HD active conformations correspond to alterations in the catalytic region that reveal the active site to NAD. Our work deepens the understanding of PARP1 catalytic activation, the dynamics of the binding site of PARP inhibitor compounds, and the mechanisms regulating PARP1 retention on DNA damage.
PARP1 能快速检测 DNA 链断裂损伤，并通过别构方式向 PARP1 催化结构域发出断裂检测信号，从而激活 NAD 来源的聚（ADP-核糖）的产生。PARP1 的激活表现为一个调节螺旋结构域（HD）的结构发生动态变化；然而，对于 HD 对 PARP1 别构的具体贡献，我们的了解非常有限。在这里，我们已经确定了 PARP1 的孤立活性状态的晶体结构，这些结构显示了特定的 HD 构象。这些捕获的快照和生化分析表明，HD 对 PARP1 多结构域和与 DNA 损伤的高亲和力相互作用有贡献，为 PARP1 别构的力学提供了新的见解，并表明 HD 的活性构象如何与催化区域的改变相对应，从而将活性位点暴露给 NAD。我们的工作加深了对 PARP1 催化激活、PARP 抑制剂化合物结合位点动力学以及 PARP1 在 DNA 损伤上保留的调控机制的理解。
