1a26
THE CATALYTIC FRAGMENT OF POLY(ADP-RIBOSE) POLYMERASE COMPLEXED WITH CARBA-NAD
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OverviewOverview
The binding site for the acceptor substrate poly(ADP-ribose) in the, elongation reaction of the ADP-ribosyl transferase poly(ADP-ribose), polymerase (PARP) was detected by cocrystallizing the enzyme with an NAD+, analogue. The site was confirmed by mutagenesis studies. In conjunction, with the binding site of the donor NAD+, the bound acceptor reveals the, geometry of the elongation reaction. It shows in particular that the, strictly conserved glutamate residue of all ADP-ribosylating enzymes, (Glu988 of PARP) facilitates the reaction by polarizing both, donor and, acceptor. Moreover, the binding properties of the acceptor site suggest a, mechanism for the branching reaction, that also explains the dual, specificity of this transferase for elongation and branching, which is, unique among polymer-forming enzymes.
About this StructureAbout this Structure
1A26 is a Single protein structure of sequence from Gallus gallus with CNA as ligand. Active as NAD(+) ADP-ribosyltransferase, with EC number 2.4.2.30 Full crystallographic information is available from OCA.
ReferenceReference
The mechanism of the elongation and branching reaction of poly(ADP-ribose) polymerase as derived from crystal structures and mutagenesis., Ruf A, Rolli V, de Murcia G, Schulz GE, J Mol Biol. 1998 Apr 24;278(1):57-65. PMID:9571033
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