晶体结构的MgtE Mg2+ 传送器的晶体结构
Motoyuki Hattori1, Yoshiki Tanaka, Shuya Fukai
1Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa 226-8501, Japan.
Nature
|August 19, 2007
概括
像MgtE这样的转运器对于细胞平衡至关重要. 结构研究揭示了MgtE如何通过感知细胞内Mg2+水平来调节离子运输.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 分子生理学分子生理学
背景情况:
- 离子 (Mg2+) 对于许多生理过程至关重要.
- 2+运输体促进2+的吸收,但它们的机制,特别是化2+的脱水,尚不清楚.
- 2+运输体的MgtE家族广泛存在,人类同类物参与的稳态.
研究的目的:
- 阐明MgtE Mg2+传送器功能的结构基础.
- 描述全长的Thermus thermophilus MgtE结构及其依赖Mg2+的形状变化.
主要方法:
- 使用X射线晶体学来确定全长MgtE及其细胞质域的结构.
- 在3.5 Å,2.3 Å和3.9 Å的分辨率下,在Mg2+的存在和缺席下解决了结构.
主要成果:
- MgtE传送器表现出具有跨膜和细胞质域的同位体结构.
- 穿过膜域的孔隙显示了潜在的Mg2+结合部位,包括Asp 432.
- 结合Mg2+与细胞质域诱导连接螺旋体的结构变化,可能调节孔隙开放.
结论:
- 结合Mg2+与MgtE的细胞质域,似乎可以调节Mg2+的流量.
- 这表明一个恒温机制,MgtE感知细胞内Mg2+度控制运输.
- 孔门的精确机制 (离子通道与二次活性运输) 需要进一步研究.
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