Schwarze Kim, Burmester Thorsten
Institute of Zoology and Zoological Museum, University of Hamburg, Hamburg, Germany.
Biochim Biophys Acta. 2013 Sep;1834(9):1801-12. doi: 10.1016/j.bbapap.2013.01.019. Epub 2013 Jan 27.
The (hemo-)globins are among the best-investigated proteins in biomedical sciences. These small heme-proteins play an important role in oxygen supply, but may also have other functions. In addition to well known hemoglobin and myoglobin, six other vertebrate globin types have been identified in recent years: neuroglobin, cytoglobin, globin E, globin X, globin Y, and androglobin. Analyses of the genome of the "living fossil" Latimeria chalumnae show that the coelacanth is the only known vertebrate that includes all eight globin types. Thus, Latimeria can also be considered as a "globin fossil". Analyses of gene synteny and phylogenetic reconstructions allow us to trace the evolution and the functional changes of the vertebrate globin family. Neuroglobin and globin X diverged from the other globin types before the separation of Protostomia and Deuterostomia. The cytoglobins, which are unlikely to be involved in O2 supply, form the earliest globin branch within the jawed vertebrates (Gnathostomata), but do not group with the agnathan hemoglobins, as it has been proposed before. There is strong evidence from phylogenetic reconstructions and gene synteny that the eye-specific globin E and muscle-specific myoglobin constitute a common clade, suggesting a similar role in intracellular O2 supply. Latimeria possesses two α- and two β-hemoglobin chains, of which one α-chain emerged prior to the divergence of Actinopterygii and Sarcopterygii, but has been retained only in the coelacanth. Notably, the embryonic hemoglobin α-chains of Gnathostomata derive from a common ancestor, while the embryonic β-chains - with the exception of a more complex pattern in the coelacanth and amphibians - display a clade-specific evolution. Globin Y is associated with the hemoglobin gene cluster, but its phylogenetic position is not resolved. Our data show an early divergence of distinct globin types in the vertebrate evolution before the emergence of tetrapods. The subsequent loss of globins in certain taxa may be associated with changes in the oxygen-dependent metabolism. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.
（血）红蛋白是生物医学领域中研究最为深入的蛋白质之一。这些小型血红素蛋白在氧气供应中发挥着重要作用，但可能也具有其他功能。除了广为人知的血红蛋白和肌红蛋白外，近年来还在脊椎动物中鉴定出了其他六种球蛋白类型：神经球蛋白、细胞球蛋白、球蛋白E、球蛋白X、球蛋白Y和雄激素球蛋白。对“活化石”腔棘鱼基因组的分析表明，腔棘鱼是唯一已知包含所有八种球蛋白类型的脊椎动物。因此，腔棘鱼也可被视为“球蛋白化石”。对基因同线性的分析和系统发育重建使我们能够追溯脊椎动物球蛋白家族的进化和功能变化。神经球蛋白和球蛋白X在原口动物和后口动物分化之前就与其他球蛋白类型分道扬镳了。细胞球蛋白不太可能参与氧气供应，它在有颌脊椎动物（Gnathostomata）中形成了最早的球蛋白分支，但并不像之前所提出的那样与无颌类血红蛋白归为一类。系统发育重建和基因同线性的有力证据表明，眼睛特异性的球蛋白E和肌肉特异性的肌红蛋白构成了一个共同的进化枝，这表明它们在细胞内氧气供应中具有相似的作用。腔棘鱼拥有两条α-和两条β-血红蛋白链，其中一条α-链在辐鳍鱼纲和肉鳍鱼纲分化之前就已出现，但仅在腔棘鱼中得以保留。值得注意的是，有颌脊椎动物的胚胎血红蛋白α-链源自一个共同的祖先，而胚胎β-链——除了腔棘鱼和两栖动物中更为复杂的模式外——呈现出进化枝特异性的进化。球蛋白Y与血红蛋白基因簇相关，但其系统发育位置尚未确定。我们的数据表明，在四足动物出现之前，脊椎动物进化过程中不同球蛋白类型就已早期分化。某些分类群中随后球蛋白的丢失可能与氧依赖代谢的变化有关。本文是名为《氧结合与传感蛋白》的特刊的一部分。
