Tocchini-Valentini Giuseppe D, Fruscoloni Paolo, Tocchini-Valentini Glauco P
Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche, Campus A. Buzzati-Traverso, Via Ramarini 32, I-00016 Monterotondo Scalo, Rome, Italy.
Proc Natl Acad Sci U S A. 2005 Jun 21;102(25):8933-8. doi: 10.1073/pnas.0502350102. Epub 2005 Jun 3.
We have detected two paralogs of the tRNA endonuclease gene of Methanocaldococcus jannaschii in the genome of the crenarchaeote Sulfolobus solfataricus. This finding has led to the discovery of a previously unrecognized oligomeric form of the enzyme. The two genes code for two different subunits, both of which are required for cleavage of the pre-tRNA substrate. Thus, there are now three forms of tRNA endonuclease in the Archaea: a homotetramer in some Euryarchaea, a homodimer in other Euryarchaea, and a heterotetramer in the Crenarchaea and the Nanoarchaea. The last-named enzyme, arising most likely by gene duplication and subsequent "subfunctionalization," requires the products of both genes to be active.
我们在嗜热栖热菌（Sulfolobus solfataricus）的基因组中检测到了詹氏甲烷球菌（Methanocaldococcus jannaschii）的tRNA内切核酸酶基因的两个旁系同源基因。这一发现促使人们发现了该酶一种以前未被识别的寡聚形式。这两个基因编码两种不同的亚基，两者都是前体tRNA底物切割所必需的。因此，古菌中现在有三种形式的tRNA内切核酸酶：一些广古菌中的同四聚体、其他广古菌中的同二聚体，以及泉古菌和纳古菌中的异四聚体。最后提到的这种酶很可能是通过基因复制和随后的“亚功能化”产生的，其活性需要两个基因的产物。
