Details

Autor(en) / Beteiligte

• Kasamatsu, Atsushi
• Nakao, Motoyuki
• Smith, Brian C.
• Comstock, Lindsay R.
• Ono, Tohru
• Kato, Jiro
• Denu, John M.
• Moss, Joel

Titel

Hydrolysis of O-Acetyl-ADP-ribose Isomers by ADP-ribosylhydrolase 3

Ist Teil von

• The Journal of biological chemistry, 2011-06, Vol.286 (24), p.21110-21117

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2011

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• O-Acetyl-ADP-ribose (OAADPr), produced by the Sir2-catalyzed NAD+-dependent histone/protein deacetylase reaction, regulates diverse biological processes. Interconversion between two OAADPr isomers with acetyl attached to the C-2″ and C-3″ hydroxyl of ADP-ribose (ADPr) is rapid. We reported earlier that ADP-ribosylhydrolase 3 (ARH3), one of three ARH proteins sharing structural similarities, hydrolyzed OAADPr to ADPr and acetate, and poly(ADPr) to ADPr monomers. ARH1 also hydrolyzed OAADPr and poly(ADPr) as well as ADP-ribose-arginine, with arginine in α-anomeric linkage to C-1″ of ADP-ribose. Because both ARH3- and ARH1-catalyzed reactions involve nucleophilic attacks at the C-1″ position, it was perplexing that the ARH3 catalytic site would cleave OAADPr at either the 2″- or 3″-position, and we postulated the existence of a third isomer, 1″-OAADPr, in equilibrium with 2″- and 3″-isomers. A third isomer, consistent with 1″-OAADPr, was identified at pH 9.0. Further, ARH3 OAADPr hydrolase activity was greater at pH 9.0 than at neutral pH where 3″-OAADPr predominated. Consistent with our hypothesis, IC50 values for ARH3 inhibition by 2″- and 3″-N-acetyl-ADPr analogs of OAADPr were significantly higher than that for ADPr. ARH1 also hydrolyzed OAADPr more rapidly at alkaline pH, but cleavage of ADP-ribose-arginine was faster at neutral pH than pH 9.0. ARH3-catalyzed hydrolysis of OAADPr in H218O resulted in incorporation of one 18O into ADP-ribose by mass spectrometric analysis, consistent with cleavage at the C-1″ position. Together, these data suggest that ARH family members, ARH1 and ARH3, catalyze hydrolysis of the 1″-O linkage in their structurally diverse substrates.