Cruz-Reyes J, Rusché L N, Piller K J, Sollner-Webb B
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Mol Cell. 1998 Feb;1(3):401-9. doi: 10.1016/s1097-2765(00)80040-4.
In the currently envisioned mechanism of trypanosome mitochondrial RNA editing, U-insertion and U-deletion cycles begin with a common kind of gRNA-directed cleavage. However, natural, altered, and mutationally interconverted editing sites reveal that U-deletional cleavage is inefficient without and activated by ATP and ADP, while U-insertional cleavage shows completely reverse nucleotide effects. The adenosine nucleotides' effects appear to be allosteric and determined solely by sequences immediately adjacent to the anchor duplex. Both U-deletional and U-insertional cleavages are reasonably active at physiological mitochondrial ATP concentration. Notably, ATP and ADP markedly stimulate complete U-deletion and inhibit U-insertion reactions, reflecting their effects on cleavage. These plus previous results suggest that U deletion and U insertion are remarkably distinct.
