The structure of ORC-Cdc6 on an origin DNA reveals the mechanism of ORC activation by the replication initiator Cdc6.
The structure of ORC-Cdc6 on an origin DNA reveals the mechanism of ORC activation by the replication initiator Cdc6.
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ORC-CDC6在起始DNA上的结构揭示了复制启动子CDC6激活ORC的机制。
DOI：
10.1038/s41467-021-24199-1
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发表时间：
2021-06-23
影响因子：
16.6
通讯作者：
Li H
中科院分区：
文献类型：
--
作者：
Feng X;Noguchi Y;Barbon M;Stillman B;Speck C;Li H
起源识别复合物（ORC）结合到染色体中的位点以指定DNA复制起点的位置。色葡萄酿酒酵母ORC在整个细胞周期中与特定的DNA序列结合，但仅当其与复制起始物Cdc 6结合时才变得有活性。目前尚不清楚Cdc 6如何在分子水平上激活ORC，将其转化为Mcm 2 -7六聚体的活跃招募者，Mcm 2 -7六聚体是复制解旋酶的核心。在这里，我们报告了与85-bp ARS 1起源DNA结合的酵母ORC-Cdc 6的3.3 Å分辨率的冷冻EM结构。结构表明，Cdc 6有助于通过其翅螺旋结构域（WHD）和其启动子特异性基序的起源DNA识别。Cdc 6结合重排Orc 1 AAA+结构域和Orc 2 WHD中的短α-螺旋，导致Cdc 6 ATP酶的激活和Mcm 2 -7募集的三个位点的形成，其中没有一个位点单独存在于ORC中。这些结果阐明了真核生物复制起点许可的关键生化步骤的分子机制。真核DNA复制由许多蛋白质介导，这些蛋白质被严格调控以在每个细胞周期有效地激发复制。在这里，作者报告了酵母ORC-Cdc 6与85 bp ARS 1起源DNA结合的冷冻电镜结构，揭示了Cdc 6如何有助于起源DNA识别的额外见解。
The Origin Recognition Complex (ORC) binds to sites in chromosomes to specify the location of origins of DNA replication. The S. cerevisiae ORC binds to specific DNA sequences throughout the cell cycle but becomes active only when it binds to the replication initiator Cdc6. It has been unclear at the molecular level how Cdc6 activates ORC, converting it to an active recruiter of the Mcm2-7 hexamer, the core of the replicative helicase. Here we report the cryo-EM structure at 3.3 Å resolution of the yeast ORC–Cdc6 bound to an 85-bp ARS1 origin DNA. The structure reveals that Cdc6 contributes to origin DNA recognition via its winged helix domain (WHD) and its initiator-specific motif. Cdc6 binding rearranges a short α-helix in the Orc1 AAA+ domain and the Orc2 WHD, leading to the activation of the Cdc6 ATPase and the formation of the three sites for the recruitment of Mcm2-7, none of which are present in ORC alone. The results illuminate the molecular mechanism of a critical biochemical step in the licensing of eukaryotic replication origins. Eukaryotic DNA replication is mediated by many proteins which are tightly regulated for an efficient firing of replication at each cell cycle. Here the authors report a cryo-EM structure of the yeast ORC–Cdc6 bound to an 85-bp ARS1 origin DNA revealing additional insights into how Cdc6 contributes to origin DNA recognition.
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影响因子：
3.3
作者：
Bell SP;Labib K
通讯作者：
Labib K
影响因子：
10.5
作者：
Eaton, Matthew L.;Galani, Kyriaki;MacAlpine, David M.
通讯作者：
MacAlpine, David M.
DOI：
10.1073/pnas.0911500106
发表时间：
2009-12-01
影响因子：
11.1
作者：
Evrin, Cecile;Clarke, Pippa;Speck, Christian
通讯作者：
Speck, Christian
DOI：
10.1073/pnas.94.11.5611
发表时间：
1997-05-27
影响因子：
11.1
作者：
Donovan, S;Harwood, J;Diffley, JFX
通讯作者：
Diffley, JFX
影响因子：
4.5
作者：
Ekundayo, Babatunde;Bleichert, Franziska
通讯作者：
Bleichert, Franziska