3q1e | pdb_00003q1e

Crystal structure of Y116T/I16A double mutant of 5-hydroxyisourate hydrolase in complex with T4

spinqualitylabelsall models 3q1e, resolution 1.95Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3q1e is a 4 chain structure with sequence from Brachidanio rerio. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: T44 Related: 2h1x, 2h6u, 3iwv Gene: urah (Brachidanio rerio) Activity: Hydroxyisourate hydrolase, with EC number 3.5.2.17 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [HIUH_DANRE] Catalyzes the hydrolysis of 5-hydroxyisourate (HIU) to 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline (OHCU). Publication Abstract from PubMed 5-Hydroxyisourate hydrolase (HIUase) and transthyretin (TTR) are closely related phylogenetically and structurally, while performing quite different functions. The former catalyzes the hydrolysis of 5-hydroxyisourate within the urate degradation pathway, and the latter is a carrier protein involved in the extracellular transport of thyroid hormones and in the cotransport of retinol. The evolution of HIUase into TTR represents a remarkable example of adaptation of a new function by active-site modification of an enzyme. On the basis of phylogenetic reconstructions and structural comparison of HIUase and TTR, two mutations (Y116T and I16A) were likely to be crucial events in order to induce, after a gene duplication event, the conversion of the enzyme into a binding protein. By rational reshaping of the active sites of HIUase and functional analyses of its mutant forms, we have provided insights into how its neofunctionalization could be achieved. We show here that the two mutations at the active sites of HIUase open up the two ends of the channel that transverses the entire tetrameric protein, generating two cavities accessible to the thyroxine molecule and abrogating, at the same time, the enzymatic activity. Our data indicate that a small number of critical mutations affecting the active site of an enzyme may be sufficient to generate a drastically different function, while a large number of additional mutations may be required for the fine-tuning of the structural and functional features of new proteins. Probing the evolution of hydroxyisourate hydrolase into transthyretin through active-site redesign.,Cendron L, Ramazzina I, Percudani R, Rasore C, Zanotti G, Berni R J Mol Biol. 2011 Jun 17;409(4):504-12. Epub 2011 Apr 16. PMID:21515285 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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