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-Structure paper
タイトル | Cryo-EM structures of the eukaryotic replicative helicase bound to a translocation substrate. |
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ジャーナル・号・ページ | Nat Commun, Vol. 7, Page 10708, Year 2016 |
掲載日 | 2016年2月18日 |
著者 | Ferdos Abid Ali / Ludovic Renault / Julian Gannon / Hailey L Gahlon / Abhay Kotecha / Jin Chuan Zhou / David Rueda / Alessandro Costa / |
PubMed 要旨 | The Cdc45-MCM-GINS (CMG) helicase unwinds DNA during the elongation step of eukaryotic genome duplication and this process depends on the MCM ATPase function. Whether CMG translocation occurs on ...The Cdc45-MCM-GINS (CMG) helicase unwinds DNA during the elongation step of eukaryotic genome duplication and this process depends on the MCM ATPase function. Whether CMG translocation occurs on single- or double-stranded DNA and how ATP hydrolysis drives DNA unwinding remain open questions. Here we use cryo-electron microscopy to describe two subnanometre resolution structures of the CMG helicase trapped on a DNA fork. In the predominant state, the ring-shaped C-terminal ATPase of MCM is compact and contacts single-stranded DNA, via a set of pre-sensor 1 hairpins that spiral around the translocation substrate. In the second state, the ATPase module is relaxed and apparently substrate free, while DNA intimately contacts the downstream amino-terminal tier of the MCM motor ring. These results, supported by single-molecule FRET measurements, lead us to suggest a replication fork unwinding mechanism whereby the N-terminal and AAA+ tiers of the MCM work in concert to translocate on single-stranded DNA. |
リンク | Nat Commun / PubMed:26888060 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 7.4 - 10.2 Å |
構造データ | EMDB-3318: EMDB-3319: EMDB-3320: EMDB-3321: |
由来 |
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