嗜热栖热菌的转移信使核糖核酸。与丙氨酰转运核糖核酸合成酶及延伸因子Tu的相互作用。

tmRNA from Thermus thermophilus. Interaction with alanyl-tRNA synthetase and elongation factor Tu.

作者信息

Stepanov Victor G, Nyborg Jens

机构信息

Institute of Molecular and Structural Biology, University of Aarhus, Denmark.

出版信息

Eur J Biochem. 2003 Feb;270(3):463-75. doi: 10.1046/j.1432-1033.2003.03401.x.

DOI:10.1046/j.1432-1033.2003.03401.x

PMID:12542696

Abstract

The interaction of a Thermus thermophilus tmRNA transcript with alanyl-tRNA synthetase and elongation factor Tu has been studied. The synthetic tmRNA was found to be stable up to 70 degrees C. The thermal optimum of tmRNA alanylation was determined to be around 50 degrees C. At 50 degrees C, tmRNA transcript was aminoacylated by alanyl-tRNA synthetase with 5.9 times lower efficiency (kcat/Km) than tRNAAla, primarily because of the difference in turnover numbers (kcat). Studies on EF-Tu protection of Ala approximately tmRNA against alkaline hydrolysis revealed the existence of at least two different binding sites for EF-Tu on charged tmRNA. The possible nature of these binding sites is discussed.

摘要

嗜热栖热菌（Thermus thermophilus）的转移信使核糖核酸（tmRNA）转录本与丙氨酰 - 转运核糖核酸合成酶及延伸因子Tu之间的相互作用已得到研究。发现合成的tmRNA在高达70摄氏度时仍保持稳定。tmRNA丙氨酰化的最适温度测定为约50摄氏度。在50摄氏度时，tmRNA转录本被丙氨酰 - 转运核糖核酸合成酶氨酰化，其效率（kcat/Km）比丙氨酰转运核糖核酸（tRNAAla）低5.9倍，这主要是由于周转数（kcat）的差异。关于延伸因子Tu对丙氨酰化tmRNA抗碱性水解的保护作用的研究表明，在带电的tmRNA上存在至少两个延伸因子Tu的不同结合位点。文中讨论了这些结合位点可能的性质。