Ligabue-Braun Rodrigo, Andreis Fábio Carrer, Verli Hugo, Carlini Célia Regina
Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
Naturwissenschaften. 2013 May;100(5):459-67. doi: 10.1007/s00114-013-1045-2. Epub 2013 Apr 26.
Ureases are nickel-dependent enzymes which catalyze the hydrolysis of urea to ammonia and carbamate. Despite the apparent wealth of data on ureases, many crucial aspects regarding these enzymes are still unknown, or constitute matter for ongoing debates. One of these is most certainly their structural organization: ureases from plants and fungi have a single unit, while bacterial and archaean ones have three-chained structures. However, the primitive state of these proteins--single- or three-chained--is yet unknown, despite many efforts in the field. Through phylogenetic inference using three different datasets and two different algorithms, we were able to observe chain number transitions displayed in a 3-to-1 fashion. Our results imply that the ancestral state for ureases is the three-chained organization, with single-chained ureases deriving from them. The two-chained variants are not evolutionary intermediates. A fusion process, different from those already studied, may explain this structural transition.
脲酶是依赖镍的酶，可催化尿素水解为氨和氨基甲酸酯。尽管关于脲酶的数据看似丰富，但这些酶的许多关键方面仍然未知，或者仍是正在进行辩论的话题。其中最肯定的一个方面是它们的结构组织：植物和真菌的脲酶具有单一单元，而细菌和古生菌的脲酶具有三链结构。然而，尽管该领域进行了许多努力，但这些蛋白质的原始状态——单链还是三链——仍然未知。通过使用三个不同的数据集和两种不同的算法进行系统发育推断，我们能够观察到以3比1的方式显示的链数转变。我们的结果表明，脲酶的祖先状态是三链组织，单链脲酶由此衍生而来。双链变体不是进化中间体。一个与已研究的过程不同的融合过程可能解释这种结构转变。
