Cryo-EM structure of human hexameric MCM2-7 complex
Naining Xu1,2, Qingpeng Lin3, Honglei Tian2
1Department of Oral and Maxillofacial Surgery, Stomatological Center, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China.
Abstract:
The central step in the initiation of eukaryotic DNA replication is the loading of the minichromosome maintenance 2-7 (MCM2-7) complex, the core of the replicative DNA helicase, onto chromatin at replication origin. Here, we reported the cryo-EM structure of endogenous human single hexameric MCM2-7 complex with a resolution at 4.4 Å, typically an open-ring hexamer with a gap between Mcm2 and Mcm5. Strikingly, further analysis revealed that human MCM2-7 can self-associate to form a loose double hexamer which potentially implies a novel mechanism underlying the MCM2-7 loading in eukaryote. The high-resolution cryo-EM structure of human MCM2-7 is critical for understanding the molecular mechanisms governing human DNA replication, especially the MCM2-7 chromatin loading and pre-replicative complex assembly.
