The structure of a deoxygenated 400 kDa hemoglobin reveals ternary and quaternary structural changes of giant hemoglobins
The structure of a deoxygenated 400 kDa hemoglobin reveals ternary and quaternary structural changes of giant hemoglobins
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脱氧 400 kDa 血红蛋白的结构揭示了巨型血红蛋白的三元和四元结构变化
DOI：
10.1107/s1399004714008475
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
K.
中科院分区：
文献类型：
--
作者：
Numoto;N.;Nakagawa;T.;Ohara;R.;Hasegawa;T.;Kita;A.;Yoshida;T.;Maruyama;T.;Imai;K.;Fukumori;Y.;and Miki;K.
无脊椎动物血红蛋白的四级结构与脊椎动物血红蛋白的四级结构有很大的不同。分子量约为400和3600 kDa的细胞外巨血红蛋白由一个圆顶形的十二聚体亚组组成，该亚组由四个单独的珠蛋白亚基组成。 已报道了来自环节动物的400 kDa血红蛋白的几种晶体结构，包括氧化和部分未配体状态的结构，但尚未报道完全脱氧状态的结构。在本研究中，晶体结构的V2Hb从管蠕虫Lamellibrachia萨摩已被确定在完全氧化和脱氧状态。一个糖基化位点和新的二价阳离子的金属结合位点，清楚地观察到没有亚基间的相互作用，在V2Hb。氧化和脱氧形式的V2Hb的比较表明，三元和四元结构的变化发生的方式，保持分子的D3对称性。这些结构表明，巨型血红蛋白的氧和脱氧状态之间的四元结构变化的机制是跨物种相同的。
The quaternary structures of invertebrate haemoglobins (Hbs) are quite different from those of vertebrate Hbs. The extracellular giant Hbs of molecular masses of about 400 and 3600 kDa are composed of a dome-shaped dodecameric subassembly which consists of four individual globin subunits. Several crystal structures of 400 kDa Hbs from annelids have been reported, including structures in oxygenated and partially unliganded states, but the structure of the fully deoxygenated state has not been reported. In the present study, crystal structures of V2Hb from the tube worm Lamellibrachia satsuma have been determined in both the fully oxygenated and deoxygenated states. A glycosylation site and novel metal-binding sites for divalent cations were clearly observed with no intersubunit interactions in V2Hb. A comparison of the oxygenated and the deoxygenated forms of V2Hb reveals that the ternary- and quaternary-structural changes occur in a manner that maintains the molecular D3 symmetry. These structures suggest that the mechanisms of quaternary-structural changes between the oxy and deoxy states for the giant Hbs are identical across species.