7x2y | pdb_00007x2y

Crystal Structure of cis-4,5-dihydrodiol phthalate dehydrogenase in complex with NAD+ and 3-Hydroxybenzoate

spinqualitylabelsall models 7x2y, resolution 2.48Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7x2y is a 2 chain structure with sequence from Comamonas testosteroni KF-1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.48Å Ligands: 3HB, GOL, NAD, PEG, PO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Phthalate cis-4,5-dihydrodiol dehydrogenase (PhtC), the second enzyme of the phthalate catabolic pathway, catalyzes the dehydrogenation of cis-4,5-dihydrodiol phthalate (DDP). Here, we report the structural and biochemical characterization of PhtC from Comamonas testosteroni KF1 (PhtCKF1). With biochemical experiments, we have determined the enzyme's catalytic efficiency (kcat/Km) with DDP as 2.6 +/- 0.5 M(-1)s(-1), over 10-fold higher than with cis-3,4-dihydrodiol phthalate (CDP). To understand the structural basis of these reactions, the crystal structures of PhtCKF1 in apo-form, the binary complex with NAD(+), and the ternary complex with NAD(+) and 3-hydroxybenzoate (3HB) were determined. These crystal structures reveal that the binding of 3HB induces a conformational change in the substrate-binding loop. This conformational change causes the opening of the NAD (+) binding site while trapping the 3HB. The PhtCKF1 crystal structures show that the catalytic domain of PhtCKF1 is larger than that of other structurally characterized homologs and does not align with other cis-diol dehydrogenases. Structural and mutational analysis of the substrate-binding loop residues, Arg164 and Glu167 establish that conformational flexibility of this loop is necessary for positioning the substrate in a catalytically competent pose, as substitution of either of these residues to Ala did not yield the dehydrogenation activity. Further, based on the crystal structures of PhtCKF1 and related structural homologs, a reaction mechanism is proposed. Finally, with the biochemical analysis of a variant M251LPhtCKF1, the broader substrate specificity of this enzyme is explained. Conformational flexibility enables catalysis of phthalate cis-4,5-dihydrodiol dehydrogenase.,Mahto JK, Sharma M, Neetu N, Kayastha A, Aggarwal S, Kumar P Arch Biochem Biophys. 2022 Sep 30;727:109314. doi: 10.1016/j.abb.2022.109314., Epub 2022 Jun 3. PMID:35667443 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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