1al8
From Proteopedia
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THREE-DIMENSIONAL STRUCTURE OF GLYCOLATE OXIDASE WITH BOUND ACTIVE-SITE INHIBITORS
Overview
A key step in plant photorespiration, the oxidation of glycolate to, glyoxylate, is carried out by the peroxisomal flavoprotein glycolate, oxidase (EC 1.1.3.15). The three-dimensional structure of this alpha/beta, barrel protein has been refined to 2 A resolution (Lindqvist Y. 1989. J, Mol Biol 209:151-166). FMN dependent glycolate oxidase is a member of the, family of alpha-hydroxy acid oxidases. Here we describe the, crystallization and structure determination of two inhibitor complexes of, the enzyme, TKP (3-Decyl-2,5-dioxo-4-hydroxy-3-pyrroline) and TACA, (4-Carboxy-5-(1-pentyl)hexylsulfanyl-1,2,3-triazole). The structure of the, TACA complex has been refined to 2.6 A resolution and the TKP complex, solved with molecular replacement, to 2.2 A resolution. The Rfree for the, TACA and TKP complexes are 24.2 and 25.1%, respectively. The overall, structures are very similar to the unliganded holoenzyme, but a closer, examination of the active site reveals differences in the positioning of, the flavin isoalloxazine ring and a displaced flexible loop in the TKP, complex. The two inhibitors differ in binding mode and hydrophobic, interactions, and these differences are reflected by the very different Ki, values for the inhibitors, 16 nM for TACA and 4.8 microM for TKP., Implications of the structures of these enzyme-inhibitor complexes for the, model for substrate binding and catalysis proposed from the holo-enzyme, structure are discussed.
About this Structure
1AL8 is a Single protein structure of sequence from Spinacia oleracea with FMN and DHP as ligands. Active as (S)-2-hydroxy-acid oxidase, with EC number 1.1.3.15 Full crystallographic information is available from OCA.
Reference
Three-dimensional structures of glycolate oxidase with bound active-site inhibitors., Stenberg K, Lindqvist Y, Protein Sci. 1997 May;6(5):1009-15. PMID:9144771
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