Mechanisms of assembly and cellular interactions for the bacterial genotoxin CDT.
Mechanisms of assembly and cellular interactions for the bacterial genotoxin CDT.
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DOI：
10.1371/journal.ppat.0010028
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发表时间：
2005-11
期刊：
影响因子：
6.7
通讯作者：
Stebbins CE
中科院分区：
文献类型：
--
作者：
Nesic D;Stebbins CE
许多引起不同疾病的细菌病原体利用细胞致死膨胀毒素（CDT）来诱导宿主细胞DNA损伤，导致细胞周期停滞或细胞凋亡。CDT是一种三联全毒素，由DNA酶I家族核酸酶（CdtB）与两个蓖麻毒素样凝集素结构域（CdtA和CdtC）结合组成。通过使用基于结构的诱变，生物化学和细胞毒性测定，我们已经检查了CdtA和CdtC亚基的几个关键结构元件，它们对毒素组装，细胞表面结合和活性的重要性。CdtA和CdtC具有N-和C-末端非小叶多肽，广泛相互作用，并与CdtB，我们已经确定了每个毒素的稳定性和活性的贡献。我们还从其晶体结构中揭示了全毒素的两个关键结合元件的功能特征。一个是CdtA中的芳香簇，另一个是在CdtA和CdtC的界面处形成的长而深的凹槽。我们表明，芳香补丁或凹槽残基的突变损害毒素与HeLa细胞的结合，细胞表面结合与培养细胞的中毒密切相关。这些结果为该毒素家族的组装和功能建立了几个基于结构的假设。细胞致死膨胀毒素被许多细菌用来破坏受感染生物体的DNA。这种DNA损伤阻止细胞分裂，最终导致细胞死亡，这增加了这种基因组损伤可能是致癌因素的可能性。细胞致死性膨胀毒素由三种蛋白质组成，它们形成紧密结合的复合物。在细菌分泌后，该复合物中的两种蛋白质粘附在细胞表面，并将第三种蛋白质递送到细胞中，在细胞中引起DNA损伤。这份报告探讨了这种毒素是如何组装的，以及它是如何粘附在宿主细胞表面的。毒素的一组分子特征被证明是至关重要的，这种细胞粘附和细胞致死膨胀毒素的能力，以抑制细胞分裂。这些结果第一次将致死性膨胀毒素的分子结构及其粘附于宿主细胞表面的能力联系在一起，有助于对这种遗传毒素的活性进行机械理解。
Many bacterial pathogens that cause different illnesses employ the cytolethal distending toxin (CDT) to induce host cell DNA damage, leading to cell cycle arrest or apoptosis. CDT is a tripartite holotoxin that consists of a DNase I family nuclease (CdtB) bound to two ricin-like lectin domains (CdtA and CdtC). Through the use of structure-based mutagenesis, biochemical and cellular toxicity assays, we have examined several key structural elements of the CdtA and CdtC subunits for their importance to toxin assembly, cell surface binding, and activity. CdtA and CdtC possess N- and C-terminal nonglobular polypeptides that extensively interact with each other and CdtB, and we have determined the contribution of each to toxin stability and activity. We have also functionally characterized two key binding elements of the holotoxin revealed from its crystal structure. One is an aromatic cluster in CdtA, and the other is a long and deep groove that is formed at the interface of CdtA and CdtC. We demonstrate that mutations of the aromatic patch or groove residues impair toxin binding to HeLa cells and that cell surface binding is tightly correlated with intoxication of cultured cells. These results establish several structure-based hypotheses for the assembly and function of this toxin family. The cytolethal distending toxin is used by many bacteria to damage the DNA of infected organisms. This DNA damage prevents cells from dividing and eventually leads to cell death, which raises the possibility that this genomic damage may be a contributing factor to carcinogenesis. The cytolethal distending toxin is composed of three proteins that form a tightly associated complex. After secretion by the bacterium, two proteins in this complex adhere to the cell surface and achieve the delivery of the third protein into the cell, where it causes DNA lesions. This report examines how this toxin is assembled and how it adheres to host cell surfaces. A set of molecular features on the toxin is shown to be critical for this cell adherence and for the ability of the cytolethal distending toxin to inhibit cell division. These results tie together for the first time aspects of the molecular structure of the cytolethal distending toxin and its ability to adhere to host cell surfaces, contributing to mechanistic understanding of the activity of this genotoxin.
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影响因子：
4.8
作者：
Cortes-Bratti, X;Karlsson, C;Frisan, T
通讯作者：
Frisan, T
影响因子：
64.8
作者：
Nesic, D;Hsu, Y;Stebbins, CE
通讯作者：
Stebbins, CE
影响因子：
3.1
作者：
Cortes-Bratti, X;Chaves-Olarte, E;Thelestam, M
通讯作者：
Thelestam, M
影响因子：
3.1
作者：
Lewis, DA;Stevens, MK;Hansen, EJ
通讯作者：
Hansen, EJ
影响因子：
3.1
作者：
Hassane, DC;Lee, RB;Pickett, CL
通讯作者：
Pickett, CL