Substrate-assisted catalysis by PARP10 limits its activity to mono-ADP-ribosylation.
ADP-ribosylation controls many processes, including transcription, DNA repair, and bacterial toxicity. ADP-ribosyltransferases and poly-ADP-ribose polymerases (PARPs) catalyze mono- and poly-ADP-ribosylation, respectively, and depend on a highly conserved glutamate residue in the active center for catalysis. However, there is an apparent absence of this glutamate for the recently described PARP6-PARP16, raising questions about how these enzymes function. We find that PARP10, in contrast to PARP1, lacks the catalytic glutamate and has transferase rather than polymerase activity. Despite this fundamental difference, PARP10 also modifies acidic residues. Consequently, we propose an alternative catalytic mechanism for PARP10 compared to PARP1 in which the acidic target residue of the substrate functionally substitutes for the catalytic glutamate by using substrate-assisted catalysis to transfer ADP-ribose. This mechanism explains why the novel PARPs are unable to function as polymerases. This discovery will help to illuminate the different biological functions of mono- versus poly-ADP-ribosylation in cells.
Institut für Biochemie und Molekularbiologie, Klinikum, RWTH Aachen University, 52057 Aachen, Germany.
Henning
H
Kleine
Elzbieta
E
Poreba
Krzysztof
K
Lesniewicz
Paul O
PO
Hassa
Michael O
MO
Hottiger
David W
DW
Litchfield
Brian H
BH
Shilton
Bernhard
B
Lüscher
D036002:ADP Ribose Transferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D020134:Catalytic Domain; D002460:Cell Line; D017124:Conserved Sequence; D006801:Humans; D066298:In Vitro Techniques; D008958:Models, Molecular; D008969:Molecular Sequence Data; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D036002:ADP Ribose Transferases; C499320:PARP1 protein, human; C499627:PARP10 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases