3CL8

Crystal structure of Puue Allantoinase complexed with ACA

Summary for 3CL8

• Entry DOI: 10.2210/pdb3cl8/pdb
• Related: 1Z7A 3CL6 3CL7
• Descriptor: Puue Allantoinase, 5-amino-1H-imidazole-4-carboxamide (3 entities in total)
• Functional Keywords: allantoine, allantoinase, uric acid degradation, amino imidazole carboximide, hydrolase
• Biological source: Pseudomonas fluorescens
• Total number of polymer chains: 2
• Total formula weight: 71188.36

Authors

Ramazzina, I.,Cendron, L.,Folli, C.,Berni, R.,Monteverdi, D.,Zanotti, G.,Percudani, R. (deposition date: 2008-03-18, release date: 2008-06-10, Last modification date: 2023-11-01)

Primary citation

Ramazzina, I.,Cendron, L.,Folli, C.,Berni, R.,Monteverdi, D.,Zanotti, G.,Percudani, R.
Logical identification of an allantoinase analog (puuE) recruited from polysaccharide deacetylases
J.Biol.Chem., 283:23295-23304, 2008

PubMed Abstract: 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.

PubMed: 18550550
DOI: 10.1074/jbc.M801195200

Experimental method

X-RAY DIFFRACTION (2.25 Å)