9E2Y

Cryo-EM structure of yeast CMG helicase stalled at G4-containing DNA template, state 3

Summary for 9E2Y

• Entry DOI: 10.2210/pdb9e2y/pdb
• EMDB information: 47472
• Descriptor: DNA replication complex GINS protein PSF1, DNA replication licensing factor MCM4, Minichromosome maintenance protein 5, ... (18 entities in total)
• Functional Keywords: helicase, dna replication, cell division, fork stalling, translocation, replication, replication-dna complex, replication/dna
• Biological source: Saccharomyces cerevisiae W303; More
• Total number of polymer chains: 14
• Total formula weight: 809694.68

Authors

Allwein, B.,Batra, S.,Remus, D.,Hite, R. (deposition date: 2024-10-23, release date: 2025-03-26)

Primary citation

Batra, S.,Allwein, B.,Kumar, C.,Devbhandari, S.,Bruning, J.G.,Bahng, S.,Lee, C.M.,Marians, K.J.,Hite, R.K.,Remus, D.
G-quadruplex-stalled eukaryotic replisome structure reveals helical inchworm DNA translocation.
Science, 387:eadt1978-eadt1978, 2025

PubMed Abstract: DNA G-quadruplexes (G4s) are non-B-form DNA secondary structures that threaten genome stability by impeding DNA replication. To elucidate how G4s induce replication fork arrest, we characterized fork collisions with preformed G4s in the parental DNA using reconstituted yeast and human replisomes. We demonstrate that a single G4 in the leading strand template is sufficient to stall replisomes by arresting the CMG helicase. Cryo-electron microscopy structures of stalled yeast and human CMG complexes reveal that the folded G4 is lodged inside the central CMG channel, arresting translocation. The G4 stabilizes the CMG at distinct translocation intermediates, suggesting an unprecedented helical inchworm mechanism for DNA translocation. These findings illuminate the eukaryotic replication fork mechanism under normal and perturbed conditions.

PubMed: 40048517
DOI: 10.1126/science.adt1978

Experimental method

ELECTRON MICROSCOPY (3.2 Å)