Substitutions in woolly mammoth hemoglobin confer biochemical properties adaptive for cold tolerance
Substitutions in woolly mammoth hemoglobin confer biochemical properties adaptive for cold tolerance
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DOI：
10.1038/ng.574
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发表时间：
2010-06-01
期刊：
影响因子：
30.8
通讯作者：
Cooper, Alan
中科院分区：
文献类型：
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作者：
Campbell, Kevin L.;Roberts, Jason E. E.;Cooper, Alan
我们已经从遗传学上检索，复活，并进行了详细的结构-功能分析，真正的羊毛猛犸血红蛋白，以揭示第一次在一个灭绝的物种的进化起源和一个关键的适应性生理化学特性的结构基础。血红蛋白结合并携带O（2）;然而，它将O（2）卸载到呼吸细胞的能力在低温下受到阻碍，因为血红素脱氧本身是吸热的（即血红蛋白-O（2）亲和力随着温度降低而增加）。我们鉴定了对猛犸血红蛋白的嵌合β/δ-珠蛋白亚基具有大表型效应的氨基酸取代，其为该问题提供了独特的解决方案，从而使能量上昂贵的热损失最小化。这种生化专业化可能已经参与了开发高纬度环境的非洲衍生的象鼻谱系在更新世时期。这种直接分析灭绝物种生理适应的遗传和结构基础的强大新方法为自然选择研究增添了重要的新维度。
We have genetically retrieved, resurrected and performed detailed structure-function analyses on authentic woolly mammoth hemoglobin to reveal for the first time both the evolutionary origins and the structural underpinnings of a key adaptive physiochemical trait in an extinct species. Hemoglobin binds and carries O(2); however, its ability to offload O(2) to respiring cells is hampered at low temperatures, as heme deoxygenation is inherently endothermic (that is, hemoglobin-O(2) affinity increases as temperature decreases). We identify amino acid substitutions with large phenotypic effect on the chimeric beta/delta-globin subunit of mammoth hemoglobin that provide a unique solution to this problem and thereby minimize energetically costly heat loss. This biochemical specialization may have been involved in the exploitation of high-latitude environments by this African-derived elephantid lineage during the Pleistocene period. This powerful new approach to directly analyze the genetic and structural basis of physiological adaptations in an extinct species adds an important new dimension to the study of natural selection.