6ptj
Structure of Ctf4 trimer in complex with one CMG helicase
Structural highlights
FunctionPSF1_YEAST Required for DNA replication. Functions as part of the GINS complex which plays an essential role in the initiation of DNA replication by binding to DNA replication origins and facilitating the assembly of the DNA replication machinery. Required for the chromatin binding of CDC45.[1] Publication Abstract from PubMedThe current view is that eukaryotic replisomes are independent. Here we show that Ctf4 tightly dimerizes CMG helicase, with an extensive interface involving Psf2, Cdc45, and Sld5. Interestingly, Ctf4 binds only one Pol alpha-primase. Thus, Ctf4 may have evolved as a trimer to organize two helicases and one Pol alpha-primase into a replication factory. In the 2CMG-Ctf43-1Pol alpha-primase factory model, the two CMGs nearly face each other, placing the two lagging strands toward the center and two leading strands out the sides. The single Pol alpha-primase is centrally located and may prime both sister replisomes. The Ctf4-coupled-sister replisome model is consistent with cellular microscopy studies revealing two sister forks of an origin remain attached and are pushed forward from a protein platform. The replication factory model may facilitate parental nucleosome transfer during replication. Ctf4 organizes sister replisomes and Pol alpha into a replication factory.,Yuan Z, Georgescu R, Santos RLA, Zhang D, Bai L, Yao NY, Zhao G, O'Donnell ME, Li H Elife. 2019 Oct 7;8. pii: 47405. doi: 10.7554/eLife.47405. PMID:31589141[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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