NADARs transcriptionally linked to DarT1s hydrolyze ADP-ribosylation on guanine (G-ADPr) and are inactive on thymine ADP-ribosylation (T-ADPr) modifications, in contrast to DarG. Guanine ADP-ribosylation is catalyzed by DarT1 and ScARP, while thymine ADP-ribosylation is catalyzed by DarT2. In vitro ADP-ribosylation assays were performed using the substrates shown in the box, with the known thymidine and guanosine nucleotides targeted for ADP-ribosylation by the characterized toxins, i.e., T. aquaticus DarT2 and S. coelicolor ScARP, highlighted with an asterisk. Representative of three independent experiments.
