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. Author manuscript; available in PMC: 2014 Aug 6.
Published in final edited form as: Nature. 2013 Dec 22;506(7486):111–115. doi: 10.1038/nature12824

Figure 1. Abortive ligation at RNA-DNA junctions is resolved by Aptx.

Figure 1

a, ATP-dependent DNA ligation: 1, ATP-dependent DNA ligase adenylation. 2, AMP is transferred to the DNA 5′ phosphate to form 5′-AMP. 3, alignment of a DNA 3′-hydroxyl with 5′-AMP within the ligase active site facilitates the nick sealing reaction. Ligase encounter with distorting termini triggers AL. b, DNA ligation is aborted at RNA-DNA junctions. Red “R” shows position of ribonucleotide. c, Quantification of total catalytic events producing sealed DNA ends (39 nt product, blue bars) or abortive DNA adenylation (red bars) by DNA ligases. Mean ± s.d. (n=2 replicates) is displayed for 60 min ligation reactions. d, hAptx DNA-adenylate hydrolysis. Reactions contained 2 nM hAptx and 10 nM of the indicated substrate.