8fdb

CRYSTAL STRUCTURE OF NAGB-II PHOSPHOSUGAR ISOMERASE FROM Shewanella denitrificans OS217 IN COMPLEX WITH GLUCITOLAMINE-6-PHOSPHATE AT 3.06 A RESOLUTION.

spinqualitylabelsall models 8fdb, resolution 3.06Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8fdb is a 2 chain structure with sequence from Shewanella denitrificans OS217. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: AGP, GOL, KCX, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q12KP2_SHEDO Publication Abstract from PubMed Glucosamine-6-phosphate (GlcN6P) deaminases from E. coli (EcNagBI) and S. denitrificans (SdNagBII) are special examples of what constitute non-homologous isofunctional enzymes due to their convergence, not only in catalysis, but also in cooperativity and allosteric properties. Additionally, we found that the sigmoidal kinetics of SdNagBII cannot be explained by the existing models of homotropic activation. This study describes the regulatory mechanism of SdNagBII using enzyme kinetics, isothermal titration calorimetry (ITC), and X-ray crystallography. ITC experiments revealed two different binding sites with distinctive thermodynamic signatures: a single binding site per monomer for the allosteric activator N-acetylglucosamine 6-phosphate (GlcNAc6P) and two binding sites per monomer for the transition-state analog 2-amino-2-deoxy-D-glucitol 6-phosphate (GlcNol6P). Crystallographic data demonstrated the existence of an unusual allosteric site that can bind both GlcNAc6P and GlcNol6P, implying that the homotropic activation of this enzyme arises from the occupation of the allosteric site by the substrate. In this work we describe the presence of this novel allosteric site in the SIS-fold deaminases, which is responsible for the homotropic and heterotropic activation of SdNagBII by GlcN6P and GlcNAc6P, respectively. This study unveils an original mechanism to generate a high degree of homotropic activation in SdNagBII, mimicking the allosteric and cooperative properties of hexameric EcNagBI but with a reduced number of subunits. This article is protected by copyright. All rights reserved. Substrate Binding in the Allosteric Site Mimics Homotropic Cooperativity in the SIS-fold Glucosamine-6-phosphate Deaminases.,Marcos-Viquez J, Rodriguez-Hernandez A, Alvarez-Anorve LI, Medina-Garcia A, Plumbridge J, Calcagno ML, Rodriguez-Romero A, Bustos-Jaimes I Protein Sci. 2023 May 5:e4651. doi: 10.1002/pro.4651. PMID:37145875 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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