Molecular Tools for the Study of ADP-Ribosylation: A Unified and Versatile Method to Synthesise Native Mono-ADP-Ribosylated Peptides

ADP-ribosylation (ADPr), as a post-translational modification, plays a crucial role in DNA-repair, immunity and many other cellular and physiological processes. Serine is the main acceptor for ADPr in DNA damage response, whereas the physiological impact of less common ADPr-modifications of cysteine and threonine side chains is less clear. Generally, gaining molecular insights into ADPr recognition and turn-over is hampered by the availability of homogeneous, ADP-ribosylated material, such as mono-ADP-ribosylated (MARylated) Peptides. Here, a new and efficient solid-phase strategy for the synthesis of Ser-, Thr- and Cys-MARylated Peptides is described. ADP-ribosylated cysteine, apart from being a native post-translational modification in its own right, proved to be suitable as a stabile bioisostere for ADP-ribosylated serine making it a useful tool to further biochemical research on serine ADP-ribosylation. In addition, it was discovered that the Streptococcus pyogenes encoded protein, SpyMacroD, acts as a Cys-(ADP-ribosyl) hydrolase.

(ADP-ribosyl) hydrolase; ADP-ribosylation; poly(ADP-ribose) polymerases; post-translational modification; solid-phase peptide synthesis.