4imd | pdb_00004imd

Crystal Structure of Pasteurella multocida N-Acetyl-D-Neuraminic acid lyase trapped with pyruvate covalently bound through a Schiff base to Lys164

spinqualitylabelsall models 4imd, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4imd is a 4 chain structure with sequence from Pasteurella multocida subsp. gallicida p1059. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: EDO, PO4 NonStd Res: KPI Related: 4imc, 4ime, 4imf, 4img Gene: nanA, PM1715 (Pasteurella multocida subsp. gallicida P1059) Activity: N-acetylneuraminate lyase, with EC number 4.1.3.3 Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed <i>N</i>-Acetylneuraminate lyases (NALs) or sialic acid aldolases catalyze the reversible aldol cleavage of <i>N</i>-acetylneuraminic acid (Neu5Ac, the most common form of sialic acid) to form pyruvate and <i>N</i>-acetyl-D-mannosamine (ManNAc). Although equilibrium favors sialic acid cleavage, these enzymes can be used for high-yield chemoenzymatic synthesis of structurally diverse sialic acids in the presence of excess pyruvate. Engineering these enzymes to synthesize structurally modified natural sialic acids and their non-natural derivatives holds promise in creating novel therapeutic agents. Atomic resolution structures of these enzymes will greatly assist in guiding mutagenic and modeling studies to engineer enzymes with altered substrate specificity. We report here the crystal structures of wild-type <i>Pasteurella multocida N</I>-acetylneuraminate lyase and its K164A mutant. Like other bacterial lyases, it assembles into a homotetramer with each monomer folding into a classic (beta/alpha)<sub>8</sub> TIM barrel. Two wild-type structures were determined; in the absence of substrates, and trapped in a Schiff base intermediate between Lys164 and pyruvate, respectively. Three structures of the K164A variant were determined: one in the absence of substrates and two binary complexes with <i>N</i>-acetylneuraminic acid (Neu5Ac) and <i>N</i>-glycolylneuraminic acid (Neu5Gc), respectively. Both sialic acids bind to the active site in the open-chain ketone form of the monosaccharide. The structures reveal that every hydroxyl group of the linear sugars makes hydrogen bond interactions with the enzyme and the residues that determine specificity were identified. Additionally, the structures lend some clues in explaining the natural discrimination of sialic acid substrates between the <i>P. multocida</i> and <i>E. coli</i> NALs. Structural basis for substrate specificity and mechanism of <i>N</i>-acetyl-D-neuraminic acid lyase from <i>Pasteurella multocida.</i>,Huynh N, Aye A, Li Y, Yu H, Cao H, Tiwari VK, Shin DW, Chen X, Fisher AJ Biochemistry. 2013 Oct 23. PMID:24152047 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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