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-Structure paper
タイトル | The structural basis for MCM2-7 helicase activation by GINS and Cdc45. |
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ジャーナル・号・ページ | Nat Struct Mol Biol, Vol. 18, Issue 4, Page 471-477, Year 2011 |
掲載日 | 2011年3月6日 |
著者 | Alessandro Costa / Ivar Ilves / Nele Tamberg / Tatjana Petojevic / Eva Nogales / Michael R Botchan / James M Berger / |
PubMed 要旨 | Two central steps for initiating eukaryotic DNA replication involve loading of the Mcm2-7 helicase onto double-stranded DNA and its activation by GINS-Cdc45. To better understand these events, we ...Two central steps for initiating eukaryotic DNA replication involve loading of the Mcm2-7 helicase onto double-stranded DNA and its activation by GINS-Cdc45. To better understand these events, we determined the structures of Mcm2-7 and the CMG complex by using single-particle electron microscopy. Mcm2-7 adopts two conformations--a lock-washer-shaped spiral state and a planar, gapped-ring form--in which Mcm2 and Mcm5 flank a breach in the helicase perimeter. GINS and Cdc45 bridge this gap, forming a topologically closed assembly with a large interior channel; nucleotide binding further seals off the discontinuity between Mcm2 and Mcm5, partitioning the channel into two smaller pores. Together, our data help explain how GINS and Cdc45 activate Mcm2-7, indicate that Mcm2-7 loading may be assisted by a natural predisposition of the hexamer to form open rings, and suggest a mechanism by which the CMG complex assists DNA strand separation. |
リンク | Nat Struct Mol Biol / PubMed:21378962 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 28.0 - 35.0 Å |
構造データ | EMDB-1832: EMDB-1833: EMDB-1834: EMDB-1835: |
由来 |
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