THE ORIGINS AND EVOLUTION OF EUKARYOTIC PROTEINS
THE ORIGINS AND EVOLUTION OF EUKARYOTIC PROTEINS
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DOI：
10.1098/rstb.1995.0107
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发表时间：
1995-09-29
影响因子：
6.3
通讯作者：
DOOLITTLE, RF
中科院分区：
文献类型：
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作者：
DOOLITTLE, RF
真核生物、古细菌和真细菌的共同祖先通过所有三个组共有的许多蛋白质的氨基酸序列比较得到了很好的证明。另一方面，有一些蛋白质，如泛素，是真核生物和古细菌共有的，但在真细菌中尚未观察到。有些蛋白质似乎完全局限于真核生物，尤其是细胞骨架蛋白。最近，肌动蛋白已被晶体学发现是同源的ATP结合域中发现的热休克蛋白和其他几种蛋白质共同所有三个urkingdoms。这一观察结果在几个方面令人困惑。大多数细胞骨架蛋白，如肌动蛋白和微管蛋白，变化非常缓慢，而且一定持续了很长时间。那么，为什么它们与所谓的原核生物的祖先没有序列相似之处呢？这个问题是通过考虑两种细菌的fts蛋白来解决的，这两种蛋白似乎一方面与肌动蛋白有关，另一方面与微管蛋白有关。一个答案可能是，这些蛋白质的变化率在其历史的关键时刻发生了巨大变化。另一种可能性是，真核生物比它们的其他一些蛋白质所显示的要古老得多。
The common ancestry of eukaryotes, archaebacteria and eubacteria is well demonstrated by amino acid sequence comparisons of numerous proteins that are common to all three groups. On the other hand, there are a few proteins, like ubiquitin, that are common to eukaryotes and archaebacteria and which have yet to be observed in eubacteria. Some proteins appear to be wholly restricted to eukaryotes; this is especially true of cytoskeletal proteins. Recently, actin has been found by crystallography to be homologous with an ATP-binding domain found in a heat shock protein and several other proteins common to all three urkingdoms. This observation is puzzling on several counts. Most cytoskeletal proteins like actin and tubulin are very slow changing and must have been so for a very long time. How is it, then, that no sequence resemblance can be discerned with their alledged prokaryotic antecedents? The question is addressed by considering two bacterial fts proteins which appear to be related to actin, on the one hand, and tubulin, on the other. One answer may be that the rate of change of these proteins changed dramatically at a key point in their history. Another possibility is that eukaryotes are much older than some of their other proteins indicate.