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运输Zn2+的P型ATP酶的结构和机制

Kaituo Wang¹, Oleg Sitsel², Gabriele Meloni³

¹1] Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark [2] Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark (K.W. and P.G.); Department of Experimental Medical Science, Lund University, Sölvegatan 19, SE-221 84 Lund, Sweden (P.G.). [3].

|August 19, 2014

概括

我们确定了在关键功能状态下输送器 (ZntA) 的晶体结构. 这揭示了细胞如何运输必需的离子,并为生物技术和医学提供了新的途径.

科学领域:

生物化学生物化学
结构生物学结构生物学
分子生物学分子生物学

背景情况:

对于细胞功能至关重要,由细胞母细胞和植物中的ZntA等载体调节.
携带2+的P型ATP酶 (ZntA) 对于的平衡和排毒至关重要.
了解ZntA结构是阐明细胞运输机制的关键.

研究的目的:

为了确定来自Shigella sonnei的ZntA在基本状态 (E2P) 和脱化中间体 (E2·Pi) 的高分辨率晶体结构.
阐明Zn(2+) 运输和释放机制的结构基础.
探索ZntA与其他P型ATPases之间的潜在联系.

主要方法:

通过X射线晶体学,以3.2 Å (E2P) 和2.7 Å (E2·Pi) 的分辨率确定ZntA结构.
蛋白质结构的分析,包括膜接口和离子结合部位.
基于脂质体的运输试验用于研究ZntA活性.

主要成果:

晶体结构揭示了ZntA的折叠,在膜接口处的两螺旋,以及导致离子结合部位的保存漏斗.
E2P结构显示了Zn(2+) 释放的开放的细胞外通路,涉及不变残留物C392,C394和D714.
E2·Pi状态显示了一个封闭的通路,D714与K693相互作用,这表明Zn2+) 释放可能受到反离子机制的刺激.
运输研究证实ZntA活动没有反运输,支持一个独特的运输机制.

结论:

这些发现为ZntA介导的运输机制提供了前所未有的结构洞察力.
结构上的相似性表明ZntA (PIB类型) 和H(+) -ATPases (PIII类型) 以及PII类型的ATPases之间存在机械联系.
这项工作为与运输和恒温相关的生物技术和生物医学应用开辟了新的可能性.

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