The DNA-binding domain of OmpR: Crystal structure of a winged helix transcription factor
The DNA-binding domain of OmpR: Crystal structure of a winged helix transcription factor
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DOI：
10.1016/s0969-2126(97)00170-6
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发表时间：
1997-01-15
期刊：
影响因子：
5.7
通讯作者：
Stock, AM
中科院分区：
文献类型：
--
作者：
MartinezHackert, E;Stock, AM
背景资料：ompF和ompC基因的差异表达受两种蛋白质调节，这两种蛋白质属于信号转导蛋白的两个组成部分家族：组氨酸激酶EnvZ和反应调节因子OmpR。OmpR属于至少50个应答调节子的亚家族，具有约98个氨基酸的同源C-末端DNA结合结构域。与已知结构的DNA结合蛋白的序列同源性不能被检测到，并且结构信息的缺乏已经阻止了对这个家族的许多功能properties.Results的理解：我们已经确定了大肠杆菌OmpR C-末端结构域的晶体结构在1.95埃分辨率，该结构由三个α螺旋包装对两个反平行β片层。两个螺旋α 2和α 3以及连接它们的十个残基环构成螺旋-转角-螺旋（HTH）基序的变体。阻碍素α 3和连接两个C-末端β链的环，β 6和β 7，可能是DNA识别位点。以前的突变研究表明，连接螺旋α 2和α 3的大环是与RNA polymerase.Conclusions的α亚基的相互作用的网站：OmpRc属于'翼螺旋-转角-螺旋' DNA结合蛋白家族。这种关系，以及许多已发表的诱变研究的结果，帮助我们解释了大多数结构元件存在于这个蛋白质结构域的功能。OmpRc的结构可能有助于帮助定义RNA聚合酶α亚基相对于与DNA结合的转录激活因子的定位。
Background: The differential expression of the ompF and ompC genes is regulated by two proteins that belong to the two component family of signal transduction proteins: the histidine kinase, EnvZ, and the response regulator, OmpR. OmpR belongs to a subfamily of at least 50 response regulators with homologous C-terminal DNA-binding domains of approximately 98 amino acids. Sequence homology with DNA-binding proteins of known structure cannot be detected, and the lack of structural information has prevented understanding of many of this family's functional properties.Results: We have determined the crystal structure of the Escherichia coli OmpR C-terminal domain at 1.95 Angstrom resolution, The structure consists of three alpha helices packed against two antiparallel beta sheets. Two helices, alpha 2 and alpha 3, and the ten residue loop connecting them constitute a variation of the helix-turn-helix (HTH) motif. Helix alpha 3 and the loop connecting the two C-terminal beta strands, beta 6 and beta 7, are probable DNA-recognition sites. Previous mutagenesis studies indicate that the large loop connecting helices alpha 2 and alpha 3 is the site of interaction with the alpha subunit of RNA polymerase.Conclusions: OmpRc belongs to the family of 'winged helix-turn-helix' DNA-binding proteins. This relationship, and the results from numerous published mutagenesis studies, have helped us to interpret the functions of most of the structural elements present in this protein domain. The structure of OmpRc could be useful in helping to define the positioning of the alpha subunit of RNA polymerase in relation to transcriptional activators that are bound to DNA.