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Title | Cryo-EM structure of a helicase loading intermediate containing ORC-Cdc6-Cdt1-MCM2-7 bound to DNA. |
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Journal, issue, pages | Nat Struct Mol Biol, Vol. 20, Issue 8, Page 944-951, Year 2013 |
Publish date | Jul 14, 2013 |
Authors | Jingchuan Sun / Cecile Evrin / Stefan A Samel / Alejandra Fernández-Cid / Alberto Riera / Hironori Kawakami / Bruce Stillman / Christian Speck / Huilin Li / |
PubMed Abstract | In eukaryotes, the Cdt1-bound replicative helicase core MCM2-7 is loaded onto DNA by the ORC-Cdc6 ATPase to form a prereplicative complex (pre-RC) with an MCM2-7 double hexamer encircling DNA. Using ...In eukaryotes, the Cdt1-bound replicative helicase core MCM2-7 is loaded onto DNA by the ORC-Cdc6 ATPase to form a prereplicative complex (pre-RC) with an MCM2-7 double hexamer encircling DNA. Using purified components in the presence of ATP-γS, we have captured in vitro an intermediate in pre-RC assembly that contains a complex between the ORC-Cdc6 and Cdt1-MCM2-7 heteroheptamers called the OCCM. Cryo-EM studies of this 14-subunit complex reveal that the two separate heptameric complexes are engaged extensively, with the ORC-Cdc6 N-terminal AAA+ domains latching onto the C-terminal AAA+ motor domains of the MCM2-7 hexamer. The conformation of ORC-Cdc6 undergoes a concerted change into a right-handed spiral with helical symmetry that is identical to that of the DNA double helix. The resulting ORC-Cdc6 helicase loader shows a notable structural similarity to the replication factor C clamp loader, suggesting a conserved mechanism of action. |
External links | Nat Struct Mol Biol / PubMed:23851460 / PubMed Central |
Methods | EM (single particle) |
Resolution | 14.0 Å |
Structure data | EMDB-5625: |
Source |
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