The mitochondrial RNA ligase from Leishmania tarentolae can join RNA molecules bridged by a complementary RNA.
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.
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Howard Hughes Medical Institute, University of California, Los Angeles School of Medicine, University of California, Los Angeles, California 90095-1662, USA.
Alfonzo
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JD
Aphasizhev
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R
Simpson
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D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D006868:Hydrolysis; D007891:Leishmania / Q000201:enzymology*; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D011130:RNA Ligase (ATP) / Q000502:physiology*; D018075:RNA, Complementary / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism; D013379:Substrate Specificity
D018075:RNA, Complementary; D012330:RNA, Double-Stranded; D000255:Adenosine Triphosphate; D011130:RNA Ligase (ATP)