5cgz | pdb_00005cgz

Crystal structure of GalB, the 4-carboxy-2-hydroxymuconate hydratase, from Pseuodomonas putida KT2440

spinqualitylabelsall models 5cgz, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5cgz is a 2 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, ZN Activity: 4-oxalmesaconate hydratase, with EC number 4.2.1.83 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Function [GALB_PSEPK] Catalyzes the conversion of oxalomesaconic acid enol (OMAenol) to 4-carboxy-4-hydroxy-2-oxoadipic acid (CHA). Mediates the third step of gallate degradation pathway. Publication Abstract from PubMed Bacterial catabolism of lignin and its breakdown products is of interest for applications in industrial processing of ligno-biomass. The gallate degradation pathway of Pseudomonas putida KT2440 requires a 4-carboxy-2-hydroxymuconate (CHM) hydratase (GalB) which has 12% sequence identity to a previously identified CHM hydratase (LigJ) from Sphingomonas sp. SYK-6. The structure of GalB was determined and found to be a member of the PIG-L N-acetyl glucosamine deacetylase family, and is structurally distinct from the amidohydrolase fold of LigJ. LigJ has the same stereo-specificity as GalB, providing an example of convergent evolution for catalytic conversion of a common metabolite in bacterial aromatic degradation pathways. Purified GalB contained bound Zn2+ cofactor; however the enzyme is capable using Fe2+ and Co2+ with similar efficiencies. The general base aspartate in the PIG-L deacetylases is an alanine in GalB; replacement of the alanine with aspartate decreased the GalB catalytic efficiency for CHM by 9.5 x 104 fold and the variant enzyme did not have any detectable hydrolase activity. Kinetic analyses and pH dependency studies of the wild-type and variant enzymes suggests roles for the Glu48 and His164 in the catalytic mechanism. Comparison to the PIG-L deacetylases has led to a proposed mechanism for GalB wherein Glu48 positions and activates the metal ligated water for the hydration reaction and His164 acts as a catalytic acid. Structural and Kinetic Characterization of the 4-Carboxy-2-Hydroxymuconate Hydratase from the Gallate and Protocatechuate 4,5-Cleavage Pathways of Pseudomonas putida KT2440.,Mazurkewich S, Brott AS, Kimber MS, Seah SY J Biol Chem. 2016 Feb 11. pii: jbc.M115.682054. PMID:26867578 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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