The functional similarity and structural diversity of human and cartilaginous fish hemoglobins.
The functional similarity and structural diversity of human and cartilaginous fish hemoglobins.
复制标题
人类和软骨鱼血红蛋白的功能相似性和结构多样性。
DOI：
10.1006/jmbi.2000.4446
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发表时间：
2001
影响因子：
5.6
通讯作者：
H. Morimoto
中科院分区：
文献类型：
--
作者：
Yukie Naoi;K. T. Chong;K. Yoshimatsu;G. Miyazaki;J. Tame;Sam;S. Adachi;H. Morimoto
尽管在生理学教科书中可以找到许多关于脊椎动物血红蛋白（Hb）适应性分子进化的描述，但它们主要基于初级结构的变化，并且更强调保护而不是功能位点的改变。然而，单靠序列分析并不能揭示蛋白质中新功能的进化。最近发现，即使在序列保守的地方，人类和一种射线（Dasyatis akajei） Hb之间也存在许多功能上重要的结构差异。我们已经解决了第二软骨鱼类（一种鲨鱼，Mustelus griseus） Hb的脱氧和CO形式的结构，并将其与人类Hb、两种硬骨鱼Hb和鳐Hb的结构进行了比较，以便更多地了解脊椎动物Hb是如何通过随机氨基酸替换的选择来实现功能进化的。软骨鱼类Hb与人Hb序列同源性略低于40%，有许多重要的功能氨基酸被替换。在Hb的分子进化过程中，比通常认为的中性更宽的取代已被接受。与鳐Hb一样，鲨鱼Hb在功能上与人类Hb表现出重要的结构差异，包括氨基酸替换和分子其他部分替换引起的保存氨基酸残基的移位。最重要的是，脱氧人Hb中的β E11Val与配体结合位点重叠，被认为在控制氧亲和力方面发挥关键作用，在鲨鱼和鳐鱼Hb中都移动了约1a。因此，适应性分子进化是可行的，因为其他氨基酸取代引起的保存氨基酸残基的功能显著突变和偏差。
Although many descriptions of adaptive molecular evolution of vertebrate hemoglobins (Hb) can be found in physiological text books, they are based mainly on changes of the primary structure and place more emphasis on conservation than alterations at the functional site. Sequence analysis alone, however, does not reveal much about the evolution of new functions in proteins. It was found recently that there are many functionally important structural differences between human and a ray (Dasyatis akajei) Hb even where sequence is conserved between the two. We have solved the structures of the deoxy and CO forms of a second cartilaginous fish (a shark, Mustelus griseus) Hb, and compared it with structures of human Hb, two bony fish Hbs and the ray Hb in order to understand more about how vertebrate Hbs have functionally evolved by the selection of random amino acid substitutions. The sequence identity of cartilaginous fish Hb and human Hb is a little less than 40 %, with many functionally important amino acid replacements. Wider substitutions than usually considered as neutral have been accepted in the course of molecular evolution of Hb. As with the ray Hb, the shark Hb shows functionally important structural differences from human Hb that involve amino acid substitutions and shifts of preserved amino acid residues induced by substitutions in other parts of the molecule. Most importantly, beta E11Val in deoxy human Hb, which overlaps the ligand binding site and is considered to play a key role in controlling the oxygen affinity, moves away about 1 A in both the shark and ray Hbs. Thus adaptive molecular evolution is feasible as a result of both functionally significant mutations and deviations of preserved amino acid residues induced by other amino acid substitutions.
影响因子：
5.6
作者：
W. Royer
通讯作者：
W. Royer