Wade Benjamin O, Liu Hon Wing, Samora Catarina P, Uhlmann Frank, Singleton Martin R
Structural Biology of Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK.
Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK.
EMBO Rep. 2017 Apr;18(4):558-568. doi: 10.15252/embr.201642825. Epub 2017 Feb 10.
Replication factor C complexes load and unload processivity clamps from DNA and are involved in multiple DNA replication and repair pathways. The RFC variant complex is required for activation of the intra-S-phase checkpoint at stalled replication forks and aids the establishment of sister chromatid cohesion. Unlike other RFC complexes, RFC contains two non-Rfc subunits, Dcc1 and Ctf8. Here, we present the crystal structure of the Dcc1-Ctf8 heterodimer bound to the C-terminus of Ctf18. We find that the C-terminus of Dcc1 contains three-winged helix domains, which bind to both ssDNA and dsDNA We further show that these domains are required for full recruitment of the complex to chromatin, and correct activation of the replication checkpoint. These findings provide the first structural data on a eukaryotic seven-subunit clamp loader and define a new biochemical activity for Dcc1.
复制因子C复合物负责在DNA上加载和卸载持续性夹子，并参与多种DNA复制和修复途径。RFC变体复合物是停滞复制叉处S期内检查点激活所必需的，有助于建立姐妹染色单体黏连。与其他RFC复合物不同，RFC包含两个非Rfc亚基，即Dcc1和Ctf8。在此，我们展示了与Ctf18 C末端结合的Dcc1-Ctf8异二聚体的晶体结构。我们发现Dcc1的C末端包含三个翼状螺旋结构域，它们既能结合单链DNA，也能结合双链DNA。我们进一步表明，这些结构域是复合物完全募集到染色质以及正确激活复制检查点所必需的。这些发现提供了关于真核七亚基夹子加载器的首个结构数据，并确定了Dcc1的一种新的生化活性。
