The solution structure of an AlcR-DNA complex sheds light onto the unique tight and monomeric DNA binding of a Zn2Cys6 protein
The solution structure of an AlcR-DNA complex sheds light onto the unique tight and monomeric DNA binding of a Zn2Cys6 protein
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DOI：
10.1016/s0969-2126(01)00640-2
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发表时间：
2001-09-01
期刊：
影响因子：
5.7
通讯作者：
Guittet, E
中科院分区：
文献类型：
--
作者：
Cahuzac, B;Cerdan, R;Guittet, E
背景：在nidulans中，转录激活子ALCR介导了a/c簇的一些基因的特异性诱导。这一簇包括与乙醇和其他醇氧化成乙酸酯有关的基因。ALCR的结合和反式激活模式在锌(2)半胱氨酸(Delta)家族中是独一无二的。到目前为止，这些特异性的结构基础还没有在原子水平上进行分析。结果：我们利用核磁共振光谱和约束分子动力学确定了10-聚DNA双链络合物中ALCR DNA结合域[ALCR(1-60)]的一系列结构。对结构的分析揭示了ALCR与DNA之间的特定相互作用，这与其他已知的锌簇合物相同。此外，ALCR锌簇上游的N末端残基参与了DNA结合，证实了R6的关键作用。蛋白质的两个额外区域与DNA的完全前所未有的特定和非特定接触被证明。结论：ALCR(1-60)-DNA复合体的结构为更好地理解ALCR系统的一些特异性提供了基础：DNA共识识别序列-通常是三联体CGG-延伸到5个碱基对，ALCR作为单体，并在主要和次要沟槽中观察到DNA结合域内外的额外接触。这些广泛的相互作用将ALCR单体稳定在其同源DNA位点上。
Background: In Aspergillus nidulans, the transcription activator AlcR mediates specific induction of a number of the genes of the a/c cluster. This cluster includes genes involved in the oxidation of ethanol and other alcohols to acetate. The pattern of binding and of transactivation of AlcR is unique within the Zn(2)Cys(delta) family. The structural bases for these specificities have not been analyzed at the atomic level until now.Results: We have used NMR spectroscopy and restrained molecular dynamics to determine a set of structures of the AlcR DNA binding domain [AlcR(1-60)] in complex with a 10-mer DNA duplex. Analysis of the structures reveals specific interactions between AlcR and DNA common to the other known zinc clusters. In addition, the involvement of the N-terminal residues upstream of the AlcR zinc cluster in DNA binding is clearly highlighted, and the pivotal role of R6 is confirmed. Totally unprecedented specific and nonspecific contacts of two additional regions of the protein with the DNA are demonstrated. The differences with the available crystallographic structures of other zinc binuclear cluster proteins-DNA complexes are analyzed.Conclusions: The structures of the AlcR(1-60)-DNA complex provide the basis for a better understanding of some of the specificities of the AlcR system: the DNA consensus recognition sequence-usually the triplet CGG-is extended to five base pairs, AlcR acts as a monomer, and additional contacts inside and outside the DNA binding domain in the major and minor groove are observed. These extensive interactions stabilize the AlcR monomer to its cognate DNA site.