Structure of a KirBac potassium channel with an open bundle crossing indicates a mechanism of channel gating.
Structure of a KirBac potassium channel with an open bundle crossing indicates a mechanism of channel gating.
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DOI：
10.1038/nsmb.2208
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发表时间：
2012-01-08
影响因子：
16.8
通讯作者：
Tucker, Stephen J.
中科院分区：
文献类型：
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作者：
Bavro, Vassiliy N.;De Zorzi, Rita;Schmidt, Matthias R.;Muniz, Joao R. C.;Zubcevic, Lejla;Sansom, Mark S. P.;Venien-Bryan, Catherine;Tucker, Stephen J.
KirBac通道是哺乳动物内矫正（Kir）钾通道的原核同源物，最近Kir和KirBac通道的晶体结构为其独特的结构结构提供了重要的见解。然而，所有可用的结构都在螺旋束交叉处关闭，因此控制其主要激活门打开的结构机制仍然未知。在这项研究中，我们设计了KirBac3.1的内层孔衬螺旋（TM2），以使束交叉形成明显的开放构象，并确定了该突变通道的晶体结构，分辨率为3.05 Å。与先前的推测相反，这种新结构提出了一种机制模型，其中细胞质结构域的旋转“扭曲”通过亚基间和亚基内相互作用的网络耦合到束交叉门的打开，该网络涉及TM2 c -连接体、滑动螺旋、g -环和cd环。
KirBac channels are prokaryotic homologs of mammalian inwardly-rectifying (Kir) potassium channels and recent crystal structures of both Kir and KirBac channels have provided a major insight into their unique structural architecture. However, all of the available structures are closed at the helix bundle-crossing and therefore the structural mechanisms that control opening of their primary activation gate remain unknown. In this study, we engineered the inner pore-lining helix (TM2) of KirBac3.1 to trap the bundle-crossing in an apparently open conformation, and determined the crystal structure of this mutant channel to 3.05 Å resolution. Contrary to previous speculation, this novel structure suggests a mechanistic model in which rotational ‘twist’ of the cytoplasmic domain is coupled to opening of the bundle-crossing gate via a network of inter- and intra-subunit interactions that involves the TM2 C-linker, slide-helix, G-loop and the CD-loop.
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影响因子：
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作者：
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通讯作者：
MacKinnon, Roderick
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影响因子：
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作者：
通讯作者：
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