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Figure 3
Chemical structures of nucleotides produced by TIR domain enzymes. ADPR, cADPR, 2′cADPR and 3′cADPR are produced by TIR domain-catalyzed hydrolysis of NAD+. Several TIR domains can also catalyze base-exchange reactions where the nicotinamide moiety of NAD+ is replaced by various heterocyclic amines such as 1 (5-iodo-iso­quinoline), 2 (1,2-di­hydro-2,7-naphthyridin-1-one), 3 (8-amino-iso­quinoline), imidazole (I) and histidine, yielding 1AD, 2AD, 3AD, IAD and His-ADPR, respectively. The red line in NAD+ shows the cleavage site that removes the nicotinamide moiety from the ADPR.

IUCrJ
Volume 11| Part 5| September 2024| Pages 695-707
ISSN: 2052-2525
https://doi.org/10.1107/S2052252524007693