3b8x | pdb_00003b8x

Crystal structure of GDP-4-keto-6-deoxymannose-3-dehydratase (ColD) H188N mutant with bound GDP-perosamine

spinqualitylabelsall models 3b8x, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3b8x is a 2 chain structure with sequence from Escherichia coli O55:H7. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.7Å Ligands: EDO, G4M, NA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q9F118_ECOLX Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Colitose is a dideoxysugar found in the O-antigen of the lipopolysaccharide that coats the outer membrane of some Gram-negative bacteria. Four enzymes are required for its production starting from D-mannose-1-phosphate and GTP. The focus of this investigation is GDP-4-keto-6-deoxy-D-mannose 3-dehydratase or ColD, which catalyzes the removal of the C3'-hydroxyl group from GDP-4-keto-6-deoxymannose. The enzyme is pyridoxal 5'-phosphate-dependent, but unlike most of these proteins, the conserved lysine residue that covalently holds the cofactor in the active site is replaced with a histidine residue. Here we describe the three-dimensional structure of ColD, determined to 1.7A resolution, whereby the active site histidine has been replaced with an asparagine residue. For this investigation, crystals of the site-directed mutant protein were grown in the presence of GDP-4-amino-4,6-dideoxy-D-mannose (GDP-perosamine). The electron density map clearly reveals the presence of the sugar analog trapped in the active site as an external aldimine. The active site is positioned between the two subunits of the dimer. Whereas the pyrophosphoryl groups of the ligand are anchored to the protein via Arg-219 and Arg-331, the hydroxyl groups of the hexose only lie within hydrogen bonding distance to ordered water molecules. Interestingly, the hexose moiety of the ligand adopts a boat rather than the typically observed chair conformation. Activity assays demonstrate that this mutant protein cannot catalyze the dehydration step. Additionally, we report data revealing that wild-type ColD is able to catalyze the production of GDP-4-keto-3,6-dideoxymannose using GDP-perosamine instead of GDP-4-keto-6-deoxymannose as a substrate. GDP-4-keto-6-deoxy-D-mannose 3-dehydratase, accommodating a sugar substrate in the active site.,Cook PD, Holden HM J Biol Chem. 2008 Feb 15;283(7):4295-303. Epub 2007 Nov 28. PMID:18045869 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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