6F0L

S. cerevisiae MCM double hexamer bound to duplex DNA

Summary for 6F0L

• Entry DOI: 10.2210/pdb6f0l/pdb
• EMDB information: 3834 3960
• Descriptor: DNA replication licensing factor MCM2, DNA replication licensing factor MCM3, DNA replication licensing factor MCM4, ... (9 entities in total)
• Functional Keywords: aaa+ helicase, nucleoprotein complex, dna replication, double hexamer, hydrolase
• Biological source: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast); More
• Total number of polymer chains: 14
• Total formula weight: 1252666.77

Authors

Abid Ali, F.,Pye, V.E.,Douglas, M.E.,Locke, J.,Nans, A.,Diffley, J.F.X.,Costa, A. (deposition date: 2017-11-20, release date: 2017-12-06, Last modification date: 2024-11-20)

Primary citation

Abid Ali, F.,Douglas, M.E.,Locke, J.,Pye, V.E.,Nans, A.,Diffley, J.F.X.,Costa, A.
Cryo-EM structure of a licensed DNA replication origin.
Nat Commun, 8:2241-2241, 2017

PubMed Abstract: Eukaryotic origins of replication are licensed upon loading of the MCM helicase motor onto DNA. ATP hydrolysis by MCM is required for loading and the post-catalytic MCM is an inactive double hexamer that encircles duplex DNA. Origin firing depends on MCM engagement of Cdc45 and GINS to form the CMG holo-helicase. CMG assembly requires several steps including MCM phosphorylation by DDK. To understand origin activation, here we have determined the cryo-EM structures of DNA-bound MCM, either unmodified or phosphorylated, and visualize a phospho-dependent MCM element likely important for Cdc45 recruitment. MCM pore loops touch both the Watson and Crick strands, constraining duplex DNA in a bent configuration. By comparing our new MCM-DNA structure with the structure of CMG-DNA, we suggest how the conformational transition from the loaded, post-catalytic MCM to CMG might promote DNA untwisting and melting at the onset of replication.

PubMed: 29269875
DOI: 10.1038/s41467-017-02389-0

Experimental method

ELECTRON MICROSCOPY (4.77 Å)