一个细胞质转激活域,对氨的吸收至关重要
D Loqué1, S Lalonde, L L Looger
1Carnegie Institution, 260 Panama St, Stanford, California 94305, USA.
Nature
|February 13, 2007
概括
氨运输体的碳氧终端作为一种全调节剂,控制营养的吸收. 这个域中的突变会使传送器失活,但共同表达可以恢复功能,揭示出一种新的调节机制.
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:
- 多种类型的膜蛋白促进了细胞膜间的营养物质运输.
- 有效的监管对于防止运输物质的有毒积累至关重要.
- 寡合氨运输体 (AMT) 对于细胞营养恒温至关重要.
研究的目的:
- 为了研究碳氧终端 (C终端) 在氨运输器功能中的调节作用.
- 阐明C端控制传送器活动的机制.
- 通过子单元相互作用来探索重建传送器功能的潜力.
主要方法:
- 在阿拉比多普西斯·塔利亚纳氨运输体的C端域的局部定向突变发生.
- 野生类型和突变载体子单元的共同表达研究.
- 对传送器活动,子单位稳定性和功能补充性的分析.
- 确定Archaeoglobus fulgidus氨运输体 (AMT) 的晶体结构.
主要成果:
- 保存的C端域中的突变取消了氨运输体活性.
- 突变载体,当与野生类型载体共同表达时,会使功能子单元失活,而不会影响稳定性.
- 在携带毛孔和C端缺陷的载体的联合表达时观察到活动的补充.
- 结构数据表明C端和邻近子单元的细胞环之间的物理相互作用.
结论:
- 寡合氨运输体的细胞质C末端作为活动必不可少的全调节器起作用.
- 通过C端介导的单体之间的形态合,允许严格调节和动态传感.
- 作为一种关键的控制机制,建议对保存的C终端位点进行酸化.
- 这种调节机制可能在细菌,真菌和植物中得到保护,并且适用于其他载体.
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