Structure and mechanism of a canonical poly(ADP-ribose) glycohydrolase.

Dunstan, Mark S; Barkauskaite, Eva; Lafite, Pierre; Knezevic, Claire E; Brassington, Amy; Ahel, Marijan; Hergenrother, Paul J; Leys, David et al. · Nat Commun · 2012

basic_science · Level V

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Abstract

Poly(ADP-ribosyl)ation is a reversible post-translational protein modification involved in the regulation of a number of cellular processes including DNA repair, chromatin structure, mitosis, transcription, checkpoint activation, apoptosis and asexual development. The reversion of poly(ADP-ribosyl)ation is catalysed by poly(ADP-ribose) (PAR) glycohydrolase (PARG), which specifically targets the unique PAR (1''-2') ribose-ribose bonds. Here we report the structure and mechanism of the first canonical PARG from the protozoan Tetrahymena thermophila. In addition, we reveal the structure of T. thermophila PARG in a complex with a novel rhodanine-containing mammalian PARG inhibitor RBPI-3. Our data demonstrate that the protozoan PARG represents a good model for human PARG and is therefore likely to prove useful in guiding structure-based discovery of new classes of PARG inhibitors.

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