在转录调节器,大肠杆菌NikRR中特异性反应
Sharon Leitch1, Michael J Bradley, Jessica L Rowe
1Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Journal of the American Chemical Society
|April 3, 2007
概括
大肠杆菌埃舍里奇亚尼克R蛋白质
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- 大肠杆菌中的Ni特异性透酶由Pnik操作子编码,由NikR蛋白调节.
- 了解NikR的金属离子特异性对于阐明其调节机制至关重要.
- 以前的研究表明,NikR在体内有特异性转录抑制.
研究的目的:
- 调查大肠杆菌NikR蛋白中金属离子特异性的结构基础.
- 阐明金属与NikR结合影响其DNA结合活性的全性机制.
- 描述金属结合的NikR复合物的独特结构特征.
主要方法:
- 采用X射线吸收光谱 (XAS) 分析了各种金属-NikR复合物 (Co,II,Ni,II,Cu,II,Cu,I,Zn,II)).
- 使用/ (H/D) 交换质谱法 (LC-ESI-MS) 来评估金属结合时的蛋白质结构变化.
- 使用XAS研究异金属复合物,以表征低亲和度金属结合部位.
主要成果:
- 高亲和度金属与NikR结合会诱导独特的蛋白质构造,Ni (II) 和Cu (II) 形成平面四坐标复合体.
- 通过H/D交换观察到NikR的金属特异性结构变化,Ni (II) 和Cu (II) 与apo-NikR相比显示出不同的交换模式.
- 低亲和度金属结合部位的特征,揭示了六个N/O-捐赠环境的Ni (II) 和类似的结构的Co (II),与化物作为一个连接体在后者情况下.
结论:
- 高亲密度金属离子的几何和连接体选择决定了NikR构造和随后的DNA结合,支持了全调节模型.
- 尼克R对不同金属离子的独特结构反应是其特异性功能的基础.
- 对高 afinity 和低 affinity 的金属结合点进行表征,可以全面了解 NikR 的金属检测机制.
相关概念视频
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