DNA double-strand breaks that initiate meiotic recombination are formed by the topoisomerase-relative enzyme Spo11, supported by conserved auxiliary factors. Because high-resolution structural data have not been available, many questions remain about the architecture of Spo11 and its partners and how they engage with DNA. We report cryo-electron microscopy structures at up to 3.3-Å resolution of DNA-bound core complexes of Saccharomyces cerevisiae Spo11 with Rec102, Rec104 and Ski8. In these structures, monomeric core complexes make extensive contacts with the DNA backbone and with the recessed 3′-OH and first 5′ overhanging nucleotide, establishing the molecular determinants of DNA end-binding specificity and providing insight into DNA cleavage preferences in vivo. The structures of individual subunits and their interfaces, supported by functional data in yeast, provide insight into the role of metal ions in DNA binding and uncover unexpected structural variation in homologs of the Top6BL component of the core complex.

启动减数分裂重组的 DNA 双链断裂是由拓扑异构酶相关酶 Spo11 形成的，并得到保守的辅助因子的支持。由于尚未获得高分辨率结构数据，因此关于 Spo11 及其合作伙伴的架构以及它们如何与 DNA 结合仍存在许多问题。我们报道了酿酒酵母Spo11 与 Rec102、Rec104 和 Ski8 的 DNA 结合核心复合物的冷冻电子显微镜结构，分辨率高达 3.3-Å。在这些结构中，单体核心复合物与 DNA 主链以及凹陷的 3'-OH 和第一个 5' 突出核苷酸进行广泛接触，建立 DNA 末端结合特异性的分子决定因素，并提供对体内 DNA 切割偏好的深入了解。各个亚基及其界面的结构由酵母中的功能数据支持，可深入了解金属离子在 DNA 结合中的作用，并揭示核心复合物 Top6BL 组件同源物中意想不到的结构变化。