'''STRUCTURE OF POLYAMINE OXIDASE IN COMPLEX WITH 1,8-DIAMINOOCTANE'''
===STRUCTURE OF POLYAMINE OXIDASE IN COMPLEX WITH 1,8-DIAMINOOCTANE===
==Overview==
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Polyamine oxidase (PAO) carries out the FAD-dependent oxidation of the secondary amino groups of spermidine and spermine, a key reaction in the polyamine catabolism. The active site of PAO consists of a 30 A long U-shaped catalytic tunnel, whose innermost part is located in front of the flavin ring. To provide insight into the PAO substrate specificity and amine oxidation mechanism, we have investigated the crystal structure of maize PAO in the reduced state and in complex with three different inhibitors, guazatine, 1,8-diaminooctane, and N(1)-ethyl-N(11)-[(cycloheptyl)methyl]-4,8-diazaundecane (CHENSpm). In the reduced state, the conformation of the isoalloxazine ring and the surrounding residues is identical to that of the oxidized enzyme. Only Lys300 moves away from the flavin to compensate for the change in cofactor protonation occurring upon reduction. The structure of the PAO.inhibitor complexes reveals an exact match between the inhibitors and the PAO catalytic tunnel. Inhibitor binding does not involve any protein conformational change. Such lock-and-key binding occurs also in the complex with CHENSpm, which forms a covalent adduct with the flavin N5 atom. Comparison of the enzyme complexes hints at an "out-of-register" mechanism of inhibition, in which the inhibitor secondary amino groups are not properly aligned with respect to the flavin to allow oxidation. Except for the Glu62-Glu170 pair, no negatively charged residues are involved in the recognition of substrate and inhibitor amino groups, which is in contrast to other polyamine binding proteins. This feature may be exploited in the design of drugs specifically targeting PAO.
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==About this Structure==
==About this Structure==
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[[Category: Flavin-dependent amine oxidase]]
[[Category: Flavin-dependent amine oxidase]]
[[Category: Oxidoreductase]]
[[Category: Oxidoreductase]]
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Revision as of 06:47, 1 July 2008
This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.
1H83 is a Single protein structure of sequence from Zea mays. Full crystallographic information is available from OCA.
ReferenceReference
Structural bases for inhibitor binding and catalysis in polyamine oxidase., Binda C, Angelini R, Federico R, Ascenzi P, Mattevi A, Biochemistry. 2001 Mar 6;40(9):2766-76. PMID:11258887
