1og4: Difference between revisions
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==Overview== | ==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 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== | ==About this Structure== | ||
1OG4 is a | 1OG4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with NAI as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/NAD(P)(+)--protein-arginine_ADP-ribosyltransferase NAD(P)(+)--protein-arginine ADP-ribosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.31 2.4.2.31] Structure known Active Site: NAI. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1OG4 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 15:03:54 2007'' | ||
