Insights into the structure and assembly of the Bacillus subtilis clamp-loader complex and its interaction with the replicative helicase.
Insights into the structure and assembly of the Bacillus subtilis clamp-loader complex and its interaction with the replicative helicase.
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DOI：
10.1093/nar/gkt173
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发表时间：
2013-05
影响因子：
14.9
通讯作者：
Oldham NJ
中科院分区：
文献类型：
--
作者：
Afonso JP;Chintakayala K;Suwannachart C;Sedelnikova S;Giles K;Hoyes JB;Soultanas P;Rafferty JB;Oldham NJ
夹夹加载复合物在DNA复制中起着至关重要的作用，它将β夹加载到引物DNA上，供复制聚合酶使用。在革兰氏阳性生物体中，人们对这种复合物的化学计量、结构和组装途径以及它如何与复制解旋酶相互作用知之甚少。质谱分析显示，异五聚体τ3-δ-δ’枯草芽孢杆菌的钳加载器可通过多种途径组装，这与革兰氏阴性模型大肠杆菌的组装途径不同。在此基础上，构建了枯草芽孢杆菌τ3-δ-δ′复合物的同源性模型，揭示了整个c端τ域的空间定位。通过x射线晶体学确定了δ亚基的结构，并表明其与大肠杆菌的结构不同，其氨基酸包含τ和δ '结合区。最值得注意的是，与大肠杆菌中的疏水相互作用相比，τ-δ相互作用在本质上似乎是亲水的。最后，τ3与复制解旋酶DnaB之间的相互作用是由DnaB中ATP/Mg2+构象的变化驱动的，并且有证据表明，DnaB六聚体水解一个ATP分子足以稳定其与τ3的相互作用。
The clamp-loader complex plays a crucial role in DNA replication by loading the β-clamp onto primed DNA to be used by the replicative polymerase. Relatively little is known about the stoichiometry, structure and assembly pathway of this complex, and how it interacts with the replicative helicase, in Gram-positive organisms. Analysis of full and partial complexes by mass spectrometry revealed that a hetero-pentameric τ3-δ-δ′ Bacillus subtilis clamp-loader assembles via multiple pathways, which differ from those exhibited by the Gram-negative model Escherichia coli. Based on this information, a homology model of the B. subtilis τ3-δ-δ′ complex was constructed, which revealed the spatial positioning of the full C-terminal τ domain. The structure of the δ subunit was determined by X-ray crystallography and shown to differ from that of E. coli in the nature of the amino acids comprising the τ and δ′ binding regions. Most notably, the τ-δ interaction appears to be hydrophilic in nature compared with the hydrophobic interaction in E. coli. Finally, the interaction between τ3 and the replicative helicase DnaB was driven by ATP/Mg2+ conformational changes in DnaB, and evidence is provided that hydrolysis of one ATP molecule by the DnaB hexamer is sufficient to stabilize its interaction with τ3.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
64.5
作者：
Jeruzalmi, D;Yurieva, O;Kuriyan, J
通讯作者：
Kuriyan, J
影响因子：
3.6
作者：
Chintakayala, Kiran;Machon, Cristina;Soultanas, Panos
通讯作者：
Soultanas, Panos
影响因子：
--
作者：
Argiriadi, MA;Goedken, ER;Kuriyan, J
通讯作者：
Kuriyan, J
影响因子：
14.8
作者：
Hernandez, Helena;Robinson, Carol V.
通讯作者：
Robinson, Carol V.