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-Structure paper
タイトル | Cryo-EM structure of a molluscan hemocyanin suggests its allosteric mechanism. |
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ジャーナル・号・ページ | Structure, Vol. 21, Issue 4, Page 604-613, Year 2013 |
掲載日 | 2013年4月2日 |
著者 | Qinfen Zhang / Xinghong Dai / Yao Cong / Junjie Zhang / Dong-Hua Chen / Matthew T Dougherty / Jiangyong Wang / Steven J Ludtke / Michael F Schmid / Wah Chiu / |
PubMed 要旨 | 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 ...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 A° cryo-EM structure of HdH1. The structure clearly shows ten 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 Ca backbone and to visualize densities corresponding to some large side chains, 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. |
リンク | Structure / PubMed:23541894 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 4.5 - 7.8 Å |
構造データ | EMDB-1648: EMDB-5585: |
由来 |
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キーワード | OXYGEN TRANSPORT / allosteric |