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-Structure paper
Title | Unwinding of a eukaryotic origin of replication visualized by cryo-EM. |
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Journal, issue, pages | Nat Struct Mol Biol, Vol. 31, Issue 8, Page 1265-1276, Year 2024 |
Publish date | May 17, 2024 |
![]() | Sarah S Henrikus / Marta H Gross / Oliver Willhoft / Thomas Pühringer / Jacob S Lewis / Allison W McClure / Julia F Greiwe / Giacomo Palm / Andrea Nans / John F X Diffley / Alessandro Costa / ![]() ![]() ![]() |
PubMed Abstract | To prevent detrimental chromosome re-replication, DNA loading of a double hexamer of the minichromosome maintenance (MCM) replicative helicase is temporally separated from DNA unwinding. Upon S-phase ...To prevent detrimental chromosome re-replication, DNA loading of a double hexamer of the minichromosome maintenance (MCM) replicative helicase is temporally separated from DNA unwinding. Upon S-phase transition in yeast, DNA unwinding is achieved in two steps: limited opening of the double helix and topological separation of the two DNA strands. First, Cdc45, GINS and Polε engage MCM to assemble a double CMGE with two partially separated hexamers that nucleate DNA melting. In the second step, triggered by Mcm10, two CMGEs separate completely, eject the lagging-strand template and cross paths. To understand Mcm10 during helicase activation, we used biochemical reconstitution with cryogenic electron microscopy. We found that Mcm10 splits the double CMGE by engaging the N-terminal homo-dimerization face of MCM. To eject the lagging strand, DNA unwinding is started from the N-terminal side of MCM while the hexamer channel becomes too narrow to harbor duplex DNA. |
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Methods | EM (single particle) |
Resolution | 3.7 - 4.5 Å |
Structure data | EMDB-17449, PDB-8p5e: EMDB-17458, PDB-8p62: EMDB-17459, PDB-8p63: ![]() EMDB-17460: S. cerevisiae sCMGE with N-ter Mcm10 density |
Chemicals | ![]() ChemComp-ATP: ![]() ChemComp-ZN: ![]() ChemComp-MG: ![]() ChemComp-ADP: |
Source |
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![]() | REPLICATION / Saccharomyces cerevisiae / helicase / CMGE / initiation of DNA replication / DNA / DNA unwinding |