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-Structure paper
Title | Molecular Basis for ATP-Hydrolysis-Driven DNA Translocation by the CMG Helicase of the Eukaryotic Replisome. |
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Journal, issue, pages | Cell Rep, Vol. 28, Issue 10, Page 2673-22688.e8, Year 2019 |
Publish date | Sep 3, 2019 |
Authors | Patrik Eickhoff / Hazal B Kose / Fabrizio Martino / Tatjana Petojevic / Ferdos Abid Ali / Julia Locke / Nele Tamberg / Andrea Nans / James M Berger / Michael R Botchan / Hasan Yardimci / Alessandro Costa / |
PubMed Abstract | In the eukaryotic replisome, DNA unwinding by the Cdc45-MCM-Go-Ichi-Ni-San (GINS) (CMG) helicase requires a hexameric ring-shaped ATPase named minichromosome maintenance (MCM), which spools single- ...In the eukaryotic replisome, DNA unwinding by the Cdc45-MCM-Go-Ichi-Ni-San (GINS) (CMG) helicase requires a hexameric ring-shaped ATPase named minichromosome maintenance (MCM), which spools single-stranded DNA through its central channel. Not all six ATPase sites are required for unwinding; however, the helicase mechanism is unknown. We imaged ATP-hydrolysis-driven translocation of the CMG using cryo-electron microscopy (cryo-EM) and found that the six MCM subunits engage DNA using four neighboring protomers at a time, with ATP binding promoting DNA engagement. Morphing between different helicase states leads us to suggest a non-symmetric hand-over-hand rotary mechanism, explaining the asymmetric requirements of ATPase function around the MCM ring of the CMG. By imaging of a higher-order replisome assembly, we find that the Mrc1-Csm3-Tof1 fork-stabilization complex strengthens the interaction between parental duplex DNA and the CMG at the fork, which might support the coupling between DNA translocation and fork unwinding. |
External links | Cell Rep / PubMed:31484077 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.7 - 4.46 Å |
Structure data | EMDB-4785: D. melanogaster CMG-DNA with ATP, State 1A EMDB-4786: D. melanogaster CMG-DNA with ATP, State 1B |
Chemicals | ChemComp-ATP: ChemComp-ADP: |
Source |
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Keywords | REPLICATION / Helicase / ATPase / AAA+ / DNA unwinding / HYDOLASE / HYDROLASE |