The DNA replication initiation protein DnaD recognises a specific strand of the Bacillus subtilis chromosome origin.
The DNA replication initiation protein DnaD recognises a specific strand of the Bacillus subtilis chromosome origin.
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DOI：
10.1093/nar/gkad277
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发表时间：
2023-05-22
影响因子：
14.9
通讯作者：
中科院分区：
文献类型：
--
作者：
基因组复制是所有生物体共有的基本生物学活动。染色体复制从起点开始双向进行，需要加载两个解旋酶，每个复制体一个。然而，支持解旋酶加载在细菌染色体起源（oriC）的分子机制尚不清楚。在这里，我们研究了模式生物枯草芽孢杆菌中的必需DNA复制起始蛋白DnaD。确定了一组ssDNA结合所需的DnaD残基，并且光交联显示该ssDNA结合区域优先与oriC的一条链相互作用。生物化学和遗传学数据支持DnaD识别位于oriC中的新的单链DNA（ssDNA）基序（DnaD识别元件（DRE））的模型。考虑到单粒子冷冻电子显微镜（cryo-EM）成像的DnaD，我们建议，在oriC内的DRE的位置编排链特异性招聘的解旋酶在DNA复制启动。这些发现大大推进了我们对细菌染色体起源的双向复制机制的理解。在枯草芽孢杆菌中，已知复制起点oriC处的基础解旋序列包含两个DnaA盒（DnaAboxes 6/7，灰色三角形）和底部链上的单链DNA结合区（DnaA-trios，绿色三角形）。主起始蛋白DnaA（绿色圆圈）结合这两个区域，并且可以提供支架以将第一解旋酶装载在底链上。在这里，我们发现了一个位于DnaA-trios对面的解旋区域的新元素，并被复制蛋白DnaD识别，我们将其命名为DnaD识别元件（DRE）。我们建议，DnaD的DRE结合促进第二个解旋酶加载事件，提供了一个途径，以实现双向DNA复制起始在细菌染色体起点。
Genome replication is a fundamental biological activity shared by all organisms. Chromosomal replication proceeds bidirectionally from origins, requiring the loading of two helicases, one for each replisome. However, the molecular mechanisms underpinning helicase loading at bacterial chromosome origins (oriC) are unclear. Here we investigated the essential DNA replication initiation protein DnaD in the model organism Bacillus subtilis. A set of DnaD residues required for ssDNA binding was identified, and photo-crosslinking revealed that this ssDNA binding region interacts preferentially with one strand of oriC. Biochemical and genetic data support the model that DnaD recognizes a new single-stranded DNA (ssDNA) motif located in oriC, the DnaD Recognition Element (DRE). Considered with single particle cryo-electron microscopy (cryo-EM) imaging of DnaD, we propose that the location of the DRE within oriC orchestrates strand-specific recruitment of helicase during DNA replication initiation. These findings significantly advance our mechanistic understanding of bidirectional replication from a bacterial chromosome origin. In Bacillus subtilis, the basal unwinding sequence at the origin of replication oriC was known to comprise two DnaA boxes (DnaAboxes6/7, grey triangles) and a single-strand DNA binding region on the bottom strand (DnaA-trios, green triangles). The master initiator protein DnaA (green circles) binds both of these regions and can provide a scaffold to load a first helicase on bottom strand. Here we discovered a new element of the unwinding region located opposite the DnaA-trios and recognised by the replication protein DnaD, which we named the DnaD Recognition Element (DRE). We propose that binding of DnaD to the DRE promotes a second helicase loading event, providing a pathway to achieve bidirectional DNA replication initiation at a bacterial chromosome origin.
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影响因子：
64.8
作者：
Jumper J;Evans R;Pritzel A;Green T;Figurnov M;Ronneberger O;Tunyasuvunakool K;Bates R;Žídek A;Potapenko A;Bridgland A;Meyer C;Kohl SAA;Ballard AJ;Cowie A;Romera-Paredes B;Nikolov S;Jain R;Adler J;Back T;Petersen S;Reiman D;Clancy E;Zielinski M;Steinegger M;Pacholska M;Berghammer T;Bodenstein S;Silver D;Vinyals O;Senior AW;Kavukcuoglu K;Kohli P;Hassabis D
通讯作者：
Hassabis D
影响因子：
4.8
作者：
Abe, Yoshito;Jo, Takaaki;Ueda, Tadashi
通讯作者：
Ueda, Tadashi
影响因子：
14.9
作者：
Collier C;Machón C;Briggs GS;Smits WK;Soultanas P
通讯作者：
Soultanas P
影响因子：
5.6
作者：
Zhang, WK;Carneiro, MJVM;Turner, IJ;Allen, S;Roberts, CJ;Soultanas, P
通讯作者：
Soultanas, P
影响因子：
3.6
作者：
Bruand, C;Velten, M;Polard, P
通讯作者：
Polard, P