Cryo-EM structure of a molluscan hemocyanin suggests its allosteric mechanism.
Cryo-EM structure of a molluscan hemocyanin suggests its allosteric mechanism.
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DOI：
10.1016/j.str.2013.02.018
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发表时间：
2013-04-02
期刊：
影响因子：
5.7
通讯作者：
Chiu, Wah
中科院分区：
文献类型：
--
作者：
Zhang, Qinfen;Dai, Xinghong;Cong, Yao;Zhang, Junjie;Chen, Dong-Hua;Dougherty, Matthew T.;Wang, Jiangyong;Ludtke, Steven J.;Schmid, Michael F.;Chiu, Wah
血蓝蛋白负责在节肢动物和软体动物血淋巴中运输O2。杂色鲍血蓝蛋白亚型1（HdH 1）是一种分子量为8 MDa的寡聚体。每个子单元由八个功能单元（FU）组成。每个FU含有两个Cu离子，其可以可逆地结合氧分子。在这里，我们报告了~4.5 μ m的冷冻电镜结构的HdH 1。该结构清楚地显示了以D5对称排列的10个不对称单元。每个不对称单元包含两个结构不同但化学上相同的亚基。该图谱的分辨率足以追踪整个亚基Cα主链，并可视化对应于一些大侧链、Cu离子对和相邻亚基相互作用网络的密度。明确地确定了非对称单元的两个子单元之间交织的FU拓扑路径。我们的观察结果表明，整个血蓝蛋白双十聚体和20个“通信集群”跨不对称单位负责其变构性质后，氧结合的稳定性的结构机制。
Hemocyanins are responsible for transporting O2 in the arthropod and molluscan hemolymph. Haliotis diversicolor molluscan hemocyanin isoform 1 (HdH1) is an 8 MDa oligomer. Each subunit is made up of eight functional units (FUs). Each FU contains two Cu ions, which can reversibly bind an oxygen molecule. Here we report a ~4.5 Å cryo-EM structure of HdH1. The structure clearly shows 10 asymmetric units arranged with D5 symmetry. Each asymmetric unit contains two structurally distinct but chemically identical subunits. The map is sufficiently resolved to trace the entire subunit Cα backbone, and to visualize densities corresponding to some large sidechains, Cu ion pairs, and interaction networks of adjacent subunits. A FU topology path intertwining between the two subunits of the asymmetric unit is unambiguously determined. Our observations suggest a structural mechanism for the stability of the entire hemocyanin didecamer and 20 “communication clusters” across asymmetric units responsible for its allosteric property upon oxygen binding.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
5.6
作者：
Cuff, ME;Miller, KI;Hendrickson, WA
通讯作者：
Hendrickson, WA
影响因子：
3
作者：
HARRIS, JR;GEBAUER, W;MARKL, J
通讯作者：
MARKL, J
影响因子：
2.4
作者：
Harris, JR;Meissner, U;Markl, J
通讯作者：
Markl, J
DOI：
10.1046/j.1432-1327.1999.00564.x
发表时间：
1999-08-01
期刊：
EUROPEAN JOURNAL OF BIOCHEMISTRY
影响因子：
--
作者：
Keller, H;Lieb, B;Markl, J
通讯作者：
Markl, J