4ipj | pdb_00004ipj

Crystal Structure of R314K N-acetyl Neuraminic Acid Synthase from Neiserria meningitidis with Malate bound

spinqualitylabelsall models 4ipj, resolution 2.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4ipj is a 1 chain structure with sequence from "diplokokkus_intracellularis_meningitidis"_(sic)_weichselbaum_1887 "diplokokkus intracellularis meningitidis" (sic) weichselbaum 1887. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: LMR, MN Related: 1xuu, 1xuz, 4ipi Gene: siaC, NMB0068 ("Diplokokkus intracellularis meningitidis" (sic) Weichselbaum 1887) Activity: N-acetylneuraminate synthase, with EC number 2.5.1.56 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed The sialic acid N-acetylneuraminic acid (NANA) has a key role in the pathogenesis of a select number of neuroinvasive bacteria such as Neisseria meningitidis. These pathogens coat themselves with polysialic acids, mimicking the exterior surface of mammalian cells and consequentially concealing the bacteria from the host's immune system. NANA is synthesized in bacteria by the homodimeric enzyme NANA synthase (NANAS), which catalyzes a condensation reaction between phosphoenolpyruvate (PEP) and N-acetylmannosamine (ManNAc). NANAS is closely related to the alpha-keto acid synthases 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase and 3-deoxy-d-manno-octulosonate 8-phosphate synthase. NANAS differs from these enzymes in that it contains an antifreeze protein like (AFPL) domain, which extends from the C-terminal of the (beta/alpha)8 barrel containing the active site and contributes a highly conserved arginine (Arg314) into the active site of the opposing monomer chain. We have investigated the role of Arg314 in NmeNANAS through mutagenesis and a combination of kinetic and structural analyses. Using isothermal titration calorimetry and molecular modeling, we have shown that Arg314 is required for the catalytic function of NANAS and that the delocalized positively charged guanidinium functionality of this residue provides steering of the sugar substrate ManNAc for suitable placement in the active site and thus reaction with PEP. Arg314 Is Essential for Catalysis by N-Acetyl Neuraminic Acid Synthase from Neisseria meningitidis.,Joseph DD, Jiao W, Parker EJ Biochemistry. 2013 Apr 5. PMID:23534460 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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