The crystal structure of the SV40 T-antigen origin binding domain in complex with DNA.
The crystal structure of the SV40 T-antigen origin binding domain in complex with DNA.
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DOI：
10.1371/journal.pbio.0050023
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发表时间：
2007-02
期刊：
影响因子：
9.8
通讯作者：
Bohm A
中科院分区：
文献类型：
--
作者：
Meinke G;Phelan P;Moine S;Bochkareva E;Bochkarev A;Bullock PA;Bohm A
DNA复制在“启动子”与复制起点结合后启动。在猿猴病毒40（SV 40）中，核心起点含有四个五核苷酸结合位点，这些位点被组织成反向重复序列对。在这里，我们描述了晶体结构的起源结合域（obd）的SV 40大T抗原（T-ag）的含有和不含一个亚片段的起源含DNA。在共结构中，两个T-ag obd以头对头的方式在DNA的同一面上取向，并且每个T-ag obd接合大沟。虽然obds在与该DNA靶结合时彼此非常接近，但它们彼此不接触。这些数据提供了一个高分辨率的结构模型，解释了位点特异性结合的起源，并表明这些相互作用如何帮助指导寡聚化事件，最终在组装的解旋酶活性的十二聚体复合物的T-ag。DNA如何复制是理解生命的关键问题。DNA复制在真核生物中仍然难以研究，其中它涉及复杂的多蛋白质装置，其在多个定义不明确的DNA序列处启动复制。这个过程在病毒系统中更容易研究，在病毒系统中，复制起点的DNA序列是明确定义的，并且只需要一个或两个蛋白质来启动复制。在猿猴病毒40（SV 40）中，大T抗原蛋白（T-ag）负责识别启动复制所需的DNA序列，称为复制起点。SV 40 T-ag也可以导致DNA解链或解旋。我们在这里报告的晶体结构的DNA结合域的SV 40 T-ag的DNA片段来自病毒复制起点。结构表明，虽然T-ag和其功能类似的蛋白质，乳头状瘤病毒E1，在这一区域没有可检测的序列同源性，但这两个结构域以相似的方式结合DNA。在这两种情况下，DNA结合被认为是启动DNA上全长蛋白质复合物的组装。有趣的是，SV 40 T-ag DNA结合结构域在与DNA结合时不相互作用。除了描述DNA-蛋白质相互作用的分子细节和由DNA结合引起的蛋白质结构的改变之外，我们还提出了一个描述随后的组装事件的模型。有和没有DNA的SV 40大T抗原（T-ag）起源结合域（obd）的晶体结构显示了两个T-ag obd如何头对头定向并与大沟接合。
DNA replication is initiated upon binding of “initiators” to origins of replication. In simian virus 40 (SV40), the core origin contains four pentanucleotide binding sites organized as pairs of inverted repeats. Here we describe the crystal structures of the origin binding domain (obd) of the SV40 large T-antigen (T-ag) both with and without a subfragment of origin-containing DNA. In the co-structure, two T-ag obds are oriented in a head-to-head fashion on the same face of the DNA, and each T-ag obd engages the major groove. Although the obds are very close to each other when bound to this DNA target, they do not contact one another. These data provide a high-resolution structural model that explains site-specific binding to the origin and suggests how these interactions help direct the oligomerization events that culminate in assembly of the helicase-active dodecameric complex of T-ag. How DNA replicates is a critical question for understanding life. DNA replication remains difficult to investigate in eukaryotes, where it involves a complex, multi-protein apparatus which initiates replication at multiple poorly-defined DNA sequences. This process is far easier to study in viral systems, where the DNA sequences at the origin of replication are well-defined and only one or two proteins are required to initiate replication. In simian virus 40 (SV40), the large T-antigen protein (T-ag) is responsible for recognizing DNA sequences required to start replication, called the origin of replication. SV40 T-ag can also cause DNA to melt or unwind. We report here the crystal structure of the DNA-binding domain of SV40 T-ag on a DNA fragment derived from the viral origin of replication. The structure shows that although T-ag and its functionally analogous protein, papilloma virus E1, share no detectable sequence homology in this region, the two domains bind the DNA in similar ways. In both cases, DNA binding is thought to initiate assembly of a complex of the full-length proteins on DNA. Interestingly, SV40 T-ag DNA-binding domains do not interact with one another when bound to DNA. In addition to describing the molecular details of the DNA–protein interactions and the alterations in protein structure induced by DNA binding, we present a model describing the subsequent assembly events. Crystal structures of the SV40 large T antigen (T-ag) origin binding domain (obd) with and without DNA show how two T-ag obds orient head-to-head and engage with the major groove.
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影响因子：
5.4
作者：
Chen, G;Stenlund, A
通讯作者：
Stenlund, A
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：
5.4
作者：
Chen, G;Stenlund, A
通讯作者：
Stenlund, A
影响因子：
11.4
作者：
Gomez-Lorenzo, MG;Valle, M;Carazo, JM
通讯作者：
Carazo, JM
影响因子：
2.9
作者：
Bradshaw, EM;Sanford, DG;Bachovchin, WW
通讯作者：
Bachovchin, WW