5c71 | pdb_00005c71

The structure of Aspergillus oryzae a-glucuronidase complexed with glycyrrhetinic acid monoglucuronide

spinqualitylabelsall models 5c71, resolution 2.62Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5c71 is a 4 chain structure with sequence from Aspergillus oryzae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.62Å Ligands: CBW, GCU Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A7XS03_ASPOZ Publication Abstract from PubMed Glycoside hydrolases (GHs) have attracted special attention in research aimed at modifying natural products by partial removal of sugar moieties to manipulate their solubility and efficacy. However, these modifications are challenging to control because the low substrate specificity of most GHs often generates undesired by-products. We previously identified a GH2-type fungal beta-glucuronidase from Aspergillus oryzae (PGUS) exhibiting promiscuous substrate specificity in hydrolysis of triterpenoid saponins. Here, we present the PGUS structure, representing the first structure of a fungal beta-glucuronidase, and that of an inactive PGUS mutant in complex with the native substrate glycyrrhetic acid 3-O-mono-beta-glucuronide (GAMG). PGUS displayed a homotetramer structure with each monomer comprising three distinct domains: a sugar-binding, an immunoglobulin-like beta-sandwich, and a TIM barrel domain. Two catalytic residues, Glu(414) and Glu(505), acted as acid/base and nucleophile, respectively. Structural and mutational analyses indicated that the GAMG glycan moiety is recognized by polar interactions with nine residues (Asp(162), His(332), Asp(414), Tyr(469), Tyr(473), Asp(505), Arg(563), Asn(567), and Lys(569)) and that the aglycone moiety is recognized by aromatic stacking and by a pi interaction with the four aromatic residues Tyr(469), Phe(470), Trp(472), and Tyr(473) Finally, structure-guided mutagenesis to precisely manipulate PGUS substrate specificity in the biotransformation of glycyrrhizin into GAMG revealed that two amino acids, Ala(365) and Arg(563), are critical for substrate specificity. Moreover, we obtained several mutants with dramatically improved GAMG yield (>95%). Structural analysis suggested that modulating the interaction of beta-glucuronidase simultaneously toward glycan and aglycone moieties is critical for tuning its substrate specificity toward triterpenoid saponins. Structure-guided engineering of the substrate specificity of a fungal beta-glucuronidase toward triterpenoid saponins.,Lv B, Sun H, Huang S, Feng X, Jiang T, Li C J Biol Chem. 2018 Jan 12;293(2):433-443. doi: 10.1074/jbc.M117.801910. Epub 2017 , Nov 16. PMID:29146597 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Glucuronisidase 3D structures

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