古细菌核糖体GTP酶结构域的研究。

Studies of the GTPase domain of archaebacterial ribosomes.

作者信息

Beauclerk A A, Hummel H, Holmes D J, Böck A, Cundliffe E

出版信息

Eur J Biochem. 1985 Sep 2;151(2):245-55. doi: 10.1111/j.1432-1033.1985.tb09095.x.

DOI:10.1111/j.1432-1033.1985.tb09095.x

Abstract

Ribosomes from the methanogens Methanococcus vannielii and Methanobacterium formicicum catalyse uncoupled hydrolysis of GTP in the presence of factor EF-2 from rat liver (but not factor EF-G from Escherichia coli). In this assay, and in poly(U)-dependent protein synthesis, they were sensitive to thiostrepton. In contrast, ribosomes from Sulfolobus solfataricus did not respond to factor EF-2 (or factor EF-G) but possessed endogenous GTPase activity, which was also sensitive to thiostrepton. Ribosomes from the methanogens did not support (p)ppGpp production, but did appear to possess the equivalent of protein L11, which in E. coli is normally required for guanosine polyphosphate synthesis. Protein L11 from E. coli bound well to 23S rRNA from all three archaebacteria (as did thiostrepton) and oligonucleotides protected by the protein were sequenced and compared with rRNA sequences from other sources.

摘要

来自嗜甲烷菌万氏甲烷球菌（Methanococcus vannielii）和甲酸甲烷杆菌（Methanobacterium formicicum）的核糖体，在存在大鼠肝脏的EF-2因子（但不存在大肠杆菌的EF-G因子）的情况下，催化GTP的非偶联水解。在该测定以及依赖于聚尿苷酸（poly(U)）的蛋白质合成中，它们对硫链丝菌素敏感。相比之下，嗜热栖热菌（Sulfolobus solfataricus）的核糖体对EF-2因子（或EF-G因子）无反应，但具有内源性GTP酶活性，该活性也对硫链丝菌素敏感。嗜甲烷菌的核糖体不支持（p）ppGpp的产生，但似乎拥有相当于大肠杆菌中鸟苷多磷酸合成通常所需的L11蛋白的物质。大肠杆菌的L11蛋白与所有三种古细菌的23S rRNA结合良好（硫链丝菌素也是如此），对该蛋白保护的寡核苷酸进行测序，并与其他来源的rRNA序列进行比较。