Petrini John, Hohl Marcel, Yu You, Kuryavyi Vitaly, Patel Dinshaw
Memorial Sloan Kettering Cancer Center.
Memorial Sloan-Kettering.
Res Sq. 2024 Dec 9:rs.3.rs-5390974. doi: 10.21203/rs.3.rs-5390974/v1.
The Mre11 complex comprises Mre11, Rad50 and Nbs1 (Xrs2 in ). The core components, Mre11 and Rad50 are highly conserved, with readily identifiable orthologs in all clades of life, whereas Nbs1/Xrs2 are present only in eukaryotes. In eukaryotes, the complex is integral to the DNA damage response, acting in DNA double strand break (DSB) detection and repair, and the activation of DNA damage signaling. We present here a 3.2 Å cryo-EM structure of the Mre11-Rad50 complex with bound dsDNA. The structure provided a foundation for detailed mutational analyses regarding homo and heterotypic protein interfaces, as well as DNA binding properties of Rad50. We define several conserved residues in Rad50 and Mre11 that are critical to complex assembly as well as for DNA binding. In addition, the data reveal that the Rad50 coiled coil domain influences ATP hydrolysis over long distances.
Mre11复合物由Mre11、Rad50和Nbs1（酵母中的Xrs2）组成。核心成分Mre11和Rad50高度保守，在所有生命进化枝中都有易于识别的直系同源物，而Nbs1/Xrs2仅存在于真核生物中。在真核生物中，该复合物是DNA损伤反应所必需的，参与DNA双链断裂（DSB）的检测和修复以及DNA损伤信号的激活。我们在此展示了结合双链DNA的Mre11-Rad50复合物的3.2埃冷冻电镜结构。该结构为关于同型和异型蛋白质界面以及Rad50的DNA结合特性的详细突变分析提供了基础。我们确定了Rad50和Mre11中几个对复合物组装以及DNA结合至关重要的保守残基。此外，数据表明Rad50卷曲螺旋结构域在远距离上影响ATP水解。
