Development and Characterization of Recombinant ADP-Ribose Binding Reagents that Allow Simultaneous Detection of Mono and Poly ADP-Ribose.

ADP-ribosylation (ADPRylation) is a post-translational modification (PTM) of proteins mediated by the activity of a variety of ADP-ribosyltransferase (ART) enzymes, such as the Poly (ADP-ribose) Polymerase (PARP) family of proteins. This PTM is diverse in both form and biological functions, which makes it a highly interesting modification, but difficult to study due to limitations in reagents available to detect the diversity of ADP-ribosylation. Recently we developed a set of recombinant antibody-like ADP-ribose binding proteins, using naturally occurring ADPR binding domains (ARBDs) that include macrodomains and WWE domains, that have been functionalized by fusion to the constant "Fc" region of rabbit immunoglobulin. Herein, we present an expansion of this biological toolkit, where we have replaced the rabbit Fc sequence with two other species, the Fc for mouse and goat immunogloblulin. Characterization of the new reagents indicates that they can be detected in a species-dependent manner, recognize specific ADP-ribose moieties, and excitingly, can be used in various antibody-based assays by co-staining. The expansion of this tool will allow for more multiplexed assessments of the complexity of ADPRylation biology in many biological systems.