Ruiz-González Mario X, Marín Ignacio
Departamento de Genética, Universidad de Valencia, Calle Doctor Moliner 50, Burjassot, 46100, Valencia, Spain.
J Mol Evol. 2006 Oct;63(4):504-12. doi: 10.1007/s00239-005-0282-1. Epub 2006 Oct 4.
Many eubacteria contain an ATP-dependent protease complex, which is built by multiple copies of the HslV and HslU proteins and is therefore called HslVU. HslU proteins are AAA + ATPases, while HslV proteins are proteases that show highly significant similarity to beta subunits of proteasomes. Therefore, the HslVU complex has been envisaged as a precursor or ancestral type of proteasome. Here we show that species of most of the main eukaryotic lineages have HslU and HslV genes very similar to those found in proteobacteria. We have detected them in amoebozoa, plantae, chromoalveolata, rhizaria, and excavata species. Phylogenetic analyses suggest that these genes have been obtained by endosymbiosis from the proteobacterial ancestor that gave rise to eukaryotic mitochondria. The products encoded by these eukaryotic genes adopt, according to modeling based on the known crystal structures of prokaryotic HslU and HslV proteins, conformations that are compatible with their being fully active, suggesting that functional HslVU complexes may be present in many eukaryotic species.
许多真细菌含有一种依赖ATP的蛋白酶复合体，它由HslV和HslU蛋白的多个拷贝组成，因此被称为HslVU。HslU蛋白是AAA + ATP酶，而HslV蛋白是蛋白酶，与蛋白酶体的β亚基具有高度显著的相似性。因此，HslVU复合体被设想为蛋白酶体的前体或祖先类型。在这里我们表明，大多数主要真核生物谱系的物种都有与变形菌中发现的HslU和HslV基因非常相似的基因。我们在变形虫、植物、色藻、根足虫和盘状动物物种中检测到了它们。系统发育分析表明，这些基因是通过内共生从产生真核生物线粒体的变形菌祖先那里获得的。根据基于原核HslU和HslV蛋白已知晶体结构的模型，这些真核基因编码的产物采用的构象与其完全活性相一致，这表明许多真核生物物种中可能存在功能性的HslVU复合体。
