通过X射线晶体学揭示的马尔托斯载体的碳催化剂抑制
Shanshuang Chen1, Michael L Oldham, Amy L Davidson
1Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
Nature
|June 18, 2013
概括
细菌通过碳催化剂抑制来调节营养吸收. 这项研究揭示了来自葡萄糖光转移酶系统的IIA (EIIA(Glc)) 酶如何抑制大肠杆菌中的马尔托斯载体.
科学领域:
- 微生物学 微生物学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- 细菌优先考虑喜欢的碳来源,如葡萄糖,以高效地使用能量.
- 由IIA酶 (EIIA(Glc) 介导的碳催化剂抑制,控制了二次碳来源的吸收.
- 由于缺乏结构数据,EIIA(Glc) 抑制载体的分子机制仍然不清楚.
研究的目的:
- 为了阐明碳催化剂抑制的分子机制.
- 为了确定EIIA的结构 (Glc) 与目标传送器复合.
- 为了了解EIIA(Glc) 如何全性抑制二次碳源吸收.
主要方法:
- 埃舍里希亚大肠杆菌EIIA的X射线晶体学 (Glc) 与马尔托斯载体 (一个ABC载体) 复合.
- 生物化学测试以确定EIIA(Glc) 突变的抑制度.
主要成果:
- 3.9 Å 晶体结构显示了两个 EIIA (((Glc) 分子与马尔托斯载体的 ATPase 子单元结合.
- 这种结合稳定了面向内部的形状,防止ATP的水解和运输.
- EIIA ((Glc) 的 N-终端区域似乎对于膜定和有效抑制至关重要.
结论:
- EIIA ((Glc) 通过稳定不活跃的形状来全性抑制马尔托斯载体.
- EIIA的N终端区域 (Glc) 增强了抑制,可能是通过在膜上缩蛋白质.
- 这项结构和生化研究为大肠杆菌中碳催化剂抑制提供了一种机制模型.
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