Structures of haemoglobin from woolly mammoth in liganded and unliganded states
Structures of haemoglobin from woolly mammoth in liganded and unliganded states
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DOI：
10.1107/s0907444912029459
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发表时间：
2012-11-01
期刊：
影响因子：
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通讯作者：
Tame, Jeremy R. H.
中科院分区：
文献类型：
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作者：
Noguchi, Hiroki;Campbell, Kevin L.;Tame, Jeremy R. H.
利用在大肠杆菌中表达的重组基因重建了已灭绝的猛犸象的血红蛋白(Hb)。珠蛋白基因序列之前是使用从冷冻身体中提取的DNA确定的。虽然与现有大象的Hb高度相似，但猛犸象的毛状蛋白质对氯离子和温度的反应相当不同。特别是，猛犸象HB的氧合热被发现要低得多，这似乎是对更新世冰河时代严酷的高纬度气候的适应，与亚洲象相比，猛犸象蛋白质对质子、氯离子和有机磷酸盐的敏感性更高。为了阐明各向同性和各向异性效应改变的结构基础，我们测定了猛犸象HB的脱氧、一氧化碳和水分子形式的晶体结构。这些模型是来自灭绝物种的Hb的第一个结构，显示了许多让人想起人类Hb的特征，但强调了对氧亲和力的精细控制不仅仅依赖于简单的整体四级结构变化。
The haemoglobin (Hb) of the extinct woolly mammoth has been recreated using recombinant genes expressed in Escherichia coli. The globin gene sequences were previously determined using DNA recovered from frozen cadavers. Although highly similar to the Hb of existing elephants, the woolly mammoth protein shows rather different responses to chloride ions and temperature. In particular, the heat of oxygenation is found to be much lower in mammoth Hb, which appears to be an adaptation to the harsh high-latitude climates of the Pleistocene Ice Ages and has been linked to heightened sensitivity of the mammoth protein to protons, chloride ions and organic phosphates relative to that of Asian elephants. To elucidate the structural basis for the altered homotropic and heterotropic effects, the crystal structures of mammoth Hb have been determined in the deoxy, carbonmonoxy and aquomet forms. These models, which are the first structures of Hb from an extinct species, show many features reminiscent of human Hb, but underline how the delicate control of oxygen affinity relies on much more than simple overall quaternary-structure changes.