结合形成的大肠杆菌变形酶的结构:了解Fe2+对Zn2+作为活性位点金属的偏好
Rinku Jain1, Bing Hao, Ren-Peng Liu
1Departments of Biochemistry and Chemistry, and Ohio State Biophysics Program, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
Journal of the American Chemical Society
|March 31, 2005
概括
铁是大肠杆菌变形酶 (PDF) 活性的首选金属. 结构研究揭示了铁的存在.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 酶学 是一种酶学.
背景情况:
- 大肠杆菌变形酶 (PDF) 从新合成的蛋白质中去除N端形式基.
- 起初,人们认为PDF是一种依赖的酶,但研究表明铁是活性金属.
- 了解金属偏好对于阐明PDF的催化机制和功能至关重要.
研究的目的:
- 调查大肠杆菌PDF不寻常的金属偏好的结构基础.
- 为了比较甲酸盐的结合,一个变形产物,铁 (Fe-PDF), (Co-PDF) 和 (Zn-PDF) 的形式.
- 为了将结构差异与观察到的酶活性差异相关联.
主要方法:
- 使用高分辨率的X射线晶体学来确定Fe-,Co-和Zn-PDF的结构.
- 对于每个酶形式,我们获得了与甲基酸盐复合的结构,甲基酸盐是变形的产物.
- 分析金属-合物相互作用和形式结合模式.
主要成果:
- 在所有三种酶形式中,甲酸与活性位点金属结合,与特定的氨基酸残留物 (Leu91, Gln50, Glu133) 相互作用.
- 在格式结合中观察到一个关键的差异:Fe-PDF和Co-PDF中的双结合,与Zn-PDF中的单结合相比.
- 这些结构变化提供了与不同金属相关的独特催化活动的见解.
结论:
- 结构数据提供了第一个证据,解释了PDF的金属依赖性活动差异.
- 铁具有较强的结合和激活甲基分裂过渡状态的能力,这可能是Fe-PDF较高活性的基础.
- 这项研究促进了对PDF的催化机制和金属离子协调的理解.
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