Pascual J, Castresana J, Saraste M
European Molecular Biology Laboratory, Heidelberg, Germany.
Bioessays. 1997 Sep;19(9):811-7. doi: 10.1002/bies.950190911.
We now know that the evolution of multidomain proteins has frequently involved genetic duplication events. These, however, are sometimes difficult to trace because of low sequence similarity between duplicated segments. Spectrin, the major component of the membrane skeleton that provides elasticity to the cell, contains tandemly repeated sequences of 106 amino acid residues. The same repeats are also present in alpha-actinin, dystrophin and utrophin. Sequence alignments and phylogenetic trees of these domains allow us to interpret the evolutionary relationship between these proteins, concluding that spectrin evolved from alpha-actinin by an elongation process that included two duplications of a block of seven repeats. This analysis shows how a modular protein unit can be used in the evolution of large cytoskeletal structures.
我们现在知道，多结构域蛋白的进化常常涉及基因复制事件。然而，由于复制片段之间的序列相似性较低，这些事件有时很难追踪。血影蛋白是膜骨架的主要成分，为细胞提供弹性，它包含106个氨基酸残基的串联重复序列。同样的重复序列也存在于α-辅肌动蛋白、肌营养不良蛋白和抗肌萎缩蛋白中。这些结构域的序列比对和系统发育树使我们能够解释这些蛋白质之间的进化关系，得出结论：血影蛋白是由α-辅肌动蛋白通过一个延伸过程进化而来的，该过程包括一个七次重复模块的两次复制。这项分析展示了一个模块化蛋白质单元是如何在大型细胞骨架结构的进化中发挥作用的。
