3cl7

Crystal structure of Puue Allantoinase in complex with Hydantoin

spinqualitylabelsall models 3cl7, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3cl7 is a 2 chain structure with sequence from Pseudomonas fluorescens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.8Å Ligands: HYN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q3KFK7_PSEPF Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The hydrolytic cleavage of the hydantoin ring of allantoin, catalyzed by allantoinase, is required for the utilization of the nitrogen present in purine-derived compounds. The allantoinase gene (DAL1), however, is missing in many completely sequenced organisms able to use allantoin as a nitrogen source. Here we show that an alternative allantoinase gene (puuE) can be precisely identified by analyzing its logic relationship with three other genes of the pathway. The novel allantoinase is annotated in structure and sequence data bases as polysaccharide deacetylase for its homology with enzymes that catalyze hydrolytic reactions on chitin or peptidoglycan substrates. The recombinant PuuE protein from Pseudomonas fluorescens exhibits metal-independent allantoinase activity and stereospecificity for the S enantiomer of allantoin. The crystal structures of the protein and of protein-inhibitor complexes reveal an overall similarity with the polysaccharide deacetylase beta/alpha barrel and remarkable differences in oligomeric assembly and active site geometry. The conserved Asp-His-His metal-binding triad is replaced by Glu-His-Trp, a configuration that is distinctive of PuuE proteins within the protein family. An extra domain at the top of the barrel offers a scaffold for protein tetramerization and forms a small substrate-binding cleft by hiding the large binding groove of polysaccharide deacetylases. Substrate positioning at the active site suggests an acid/base mechanism of catalysis in which only one member of the catalytic pair of polysaccharide deacetylases has been conserved. These data provide a structural rationale for the shifting of substrate specificity that occurred during evolution. Logical identification of an allantoinase analog (puuE) recruited from polysaccharide deacetylases.,Ramazzina I, Cendron L, Folli C, Berni R, Monteverdi D, Zanotti G, Percudani R J Biol Chem. 2008 Aug 22;283(34):23295-304. Epub 2008 Jun 12. PMID:18550550 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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