Download MendeleyStructure of human ADP-ribosyl-acceptor hydrolase 3 bound to ADP-ribose reveals a conformational switch that enables specific substrate recognition.
Pourfarjam, Y., Ventura, J., Kurinov, I., Cho, A., Moss, J., Kim, I.K.(2018) J Biol Chem 293: 12350-12359
- PubMed: 29907568
- DOI: https://doi.org/10.1074/jbc.RA118.003586
- Primary Citation of Related Structures:
6D36, 6D3A - PubMed Abstract:
ADP-ribosyl-acceptor hydrolase 3 (ARH3) plays important roles in regulation of poly(ADP-ribosyl)ation, a reversible post-translational modification, and in maintenance of genomic integrity. ARH3 degrades poly(ADP-ribose) to protect cells from poly(ADP-ribose)-dependent cell death, reverses serine mono(ADP-ribosyl)ation, and hydrolyzes O -acetyl-ADP-ribose, a product of Sirtuin-catalyzed histone deacetylation. ARH3 preferentially hydrolyzes O -linkages attached to the anomeric C1″ of ADP-ribose; however, how ARH3 specifically recognizes and cleaves structurally diverse substrates remains unknown. Here, structures of full-length human ARH3 bound to ADP-ribose and Mg 2+ , coupled with computational modeling, reveal a dramatic conformational switch from closed to open states that enables specific substrate recognition. The glutamate flap, which blocks substrate entrance to Mg 2+ in the unliganded closed state, is ejected from the active site when substrate is bound. This closed-to-open transition significantly widens the substrate-binding channel and precisely positions the scissile 1″- O -linkage for cleavage while securing tightly 2″- and 3″-hydroxyls of ADP-ribose. Our collective data uncover an unprecedented structural plasticity of ARH3 that supports its specificity for the 1″- O -linkage in substrates and Mg 2+ -dependent catalysis.
Organizational Affiliation:
From the Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221.
