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1og3
From Proteopedia
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CRYSTAL STRUCTURE OF THE EUCARYOTIC MONO-ADP-RIBOSYLTRANSFERASE ART2.2 MUTANT E189I IN COMPLEX WITH NAD
Overview
The structures of beta-methylenethiazole-4-carboxamide adenine, dinucleotide (TAD), NAD(+), and NADH as bound to, ecto-ADP-ribosyltransferase 2.2 from rat and to its mutants E189I and, E189A, respectively, have been established. The positions and, conformations of NAD(+) and its analogues agree in general with those in, other ADP-ribosyltransferases. The kinetic constants for NAD(+) hydrolysis, were determined by RP-HPLC. The specific activity amounts to 26 units/mg, which is 6000-fold higher than a previously reported rate and 500-fold, higher than the hydrolysis rates of other ADP-ribosyltransferases, confirming that hydrolysis is the major function of this enzyme. On the, basis of structures and mutant activities, a catalytic mechanism is, proposed. The known auto-ADP-ribosylation of the enzyme at the suggested, position R184 is supported by one of the crystal structures where the, nucleophile position is occupied by an Neta atom of this arginine which in, turn is backed up by the base E159.
About this Structure
1OG3 is a Single protein structure of sequence from Rattus norvegicus with as ligand. Active as NAD(P)(+)--protein-arginine ADP-ribosyltransferase, with EC number 2.4.2.31 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Substrate binding and catalysis of ecto-ADP-ribosyltransferase 2.2 from rat., Ritter H, Koch-Nolte F, Marquez VE, Schulz GE, Biochemistry. 2003 Sep 2;42(34):10155-62. PMID:12939142
Page seeded by OCA on Sun Feb 3 09:57:40 2008
