Blanc V, Alfonzo J D, Aphasizhev R, Simpson L
Howard Hughes Medical Institute, University of California, Los Angeles School of Medicine, University of California, Los Angeles, California 90095-1662, USA.
J Biol Chem. 1999 Aug 20;274(34):24289-96. doi: 10.1074/jbc.274.34.24289.
A biochemical characterization was performed with a partially purified RNA ligase from isolated mitochondria of Leishmania tarentolae. This ligase has a K(m) of 25 +/- 0.75 nM and a V(max) of 1.0 x 10(-4) +/- 2.4 x 10(-4) nmol/min when ligating a nicked double-stranded RNA substrate. Ligation was negatively affected by a gap between the donor and acceptor nucleotides. The catalytic efficiency of the circularization of a single-stranded substrate was 5-fold less than that of the ligation of a nicked substrate. These properties of the mitochondrial RNA ligase are consistent with an expected in vivo role in the process of uridine insertion/deletion RNA editing, in which the mRNA cleavage fragments are bridged by a cognate guide RNA.
对来自热带利什曼原虫分离线粒体的部分纯化RNA连接酶进行了生化特性分析。当连接带切口的双链RNA底物时，这种连接酶的米氏常数（K(m)）为25±0.75 nM，最大反应速度（V(max)）为1.0×10⁻⁴±2.4×10⁻⁴ nmol/分钟。供体和受体核苷酸之间的间隙对连接有负面影响。单链底物环化的催化效率比带切口底物连接的催化效率低5倍。线粒体RNA连接酶的这些特性与尿苷插入/缺失RNA编辑过程中预期的体内作用一致，在该过程中，mRNA切割片段由同源引导RNA桥接。
