一个H+/Ca2+交换机的反运输机制的结构基础
Tomohiro Nishizawa1, Satomi Kita, Andrés D Maturana
1Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
Science (New York, N.Y.)
|May 25, 2013
概括
这项研究揭示了反子/交换器 (CAX_Af) 在向内状态下的晶体结构. 它揭示了和质子结合如何驱动传送器.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 膜运输 运输 膜运输
背景情况:
- /离子反载体通过在膜上与其他离子交换Ca2+) 来调节细胞内水平.
- 了解这些载体的结构机制对于破译细胞平衡至关重要.
- 之前的研究揭示了一种 prokaryotic Na(+) / Ca(2+) 交换器 (NCX_Mj) 的面向外的状态.
研究的目的:
- 为了确定来自Archaeoglobus fulgidus的H ((+) /Ca ((2+) 交换器 (CAX_Af) 的晶体结构.
- 为了阐明CAX_Af.的向内变形.
- 提供关于转运机制和交换机的构造变化的见解.
主要方法:
- 在2.3 Å分辨率的X射线晶体学.
- 在两个代表性的向内转向形状中,对CAX_Af的结构性确定.
- 在CAX_Af和NCX_Mj之间进行比较结构分析.
主要成果:
- 确定了CAX_Af在向内面的状态中的晶体结构.
- 结构数据表明,2+或+在离子结合点的结合是相互排斥的.
- 与NCX_Mj的比较凸显了跨膜螺旋在形成细胞内和细胞外腔的交替作用.
结论:
- 确定的结构提供了一个详细的视图的内向的形状的H (+) /Ca (2+) 交换器.
- 这些发现表明一种机制,其中Ca2+) 和H2+) 结合触发了向内和向外状态之间的过渡.
- 这项研究加深了对生物膜中阴离子交换机制的理解.
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