Cryo-EM structure of Mcm2-7 double hexamer on DNA suggests a lagging-strand DNA extrusion model

• DOI: 10.1073/pnas.1712537114
• Publication Date: 2017-10-25T19:55:42Z
• Authors: Yasunori Noguchi; Zuanning Yuan; Lin Bai; Sarah Schneider; Gongpu Zhao; Bruce Stillman; Christian Speck; Huilin Li
• Keywords: Random hexamer; Replisome; Prokaryotic DNA replication

Significance During initiation of DNA replication in eukaryotes, the origin recognition complex, with Cdc6 and Cdt1, assembles an inactive Mcm2-7 double hexamer on dsDNA. Later, recruits Cdc45 GINS to form two active separate helicases. The Cdc45–Mcm2-7–GINS helicase encircles leading strand while excluding lagging strand. One fundamental unanswered questions is how each converts from binding dsDNA one single strands. structure reveals interacts key elements inside central channel, us propose a lagging-strand extrusion mechanism. This work advances our understanding eukaryotic initiation.