4eac | pdb_00004eac

Crystal structure of mannonate dehydratase from Escherichia coli strain K12

spinqualitylabelsall models 4eac, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4eac is a 4 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL, MN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [UXUA_ECOLI] Catalyzes the dehydration of D-mannonate. Publication Abstract from PubMed Mannonate dehydratase (ManD; EC4.2.1.8) catalyzes the dehydration of D-mannonate to 2-keto-3-deoxygluconate. It is the third enzyme in the pathway for dissimilation of D-glucuronate to 2-keto-3-deoxygluconate involving in the Entner-Doudoroff pathway in certain bacterial and archaeal species. ManD from Gram negative bacteria has an insert sequence as compared to those from Gram positives revealed by sequence analysis. To evaluate the impact of this insert sequence on the catalytic efficiency, we solved the crystal structures of ManD from Escherichia coli strain K12 and its complex with D-mannonate, which reveal that this insert sequence forms two alpha helices locating above the active site. The two insert alpha helices introduce a loop that forms a cap covering the substrate binding pocket, which restricts the tunnels of substrate entering and product releasing from the active site. Site-directed mutations and enzymatic activity assays confirm that the catalytic rate is decreased by this loop. These features are conserved among Gram negative bacteria. Thus, the insert sequence of ManD from Gram negative bacteria acts as a common inducer to decrease the catalytic rate and consequently the glucuronate metabolic rate as compared to those from Gram positives. Moreover, residues essential for substrate to enter the active site were characterized via structural analysis and enzymatic activity assays. Structural insights into decreased enzymatic activity induced by an insert sequence in mannonate dehydratase from Gram negative bacterium.,Qiu X, Tao Y, Zhu Y, Yuan Y, Zhang Y, Liu H, Gao Y, Teng M, Niu L J Struct Biol. 2012 Nov;180(2):327-34. doi: 10.1016/j.jsb.2012.06.013. Epub 2012 , Jul 14. PMID:22796868 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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