Abstract
A vitamin B(6) degradative pathway has recently been identified and characterized in Mesorhizobium loti MAFF303099. One of the enzymes on this pathway, 2-methyl-3-hydroxypyridine-5-carboxylic acid oxygenase (MHPCO), is a flavin-dependent enzyme and catalyzes the oxidative ring-opening of 2-methyl-3-hydroxypyridine-5-carboxylic acid to form E-2-(acetamino-methylene)succinate. The gene for this enzyme has been cloned, and the corresponding protein has been overexpressed in Escherichia coli and purified. The crystal structure of MHPCO has been solved to 2.1 A using SAD phasing with and without the substrate MHPC bound. These crystal structures provide insight into the reaction mechanism and suggest roles for active site residues in the catalysis of a novel oxidative ring-opening reaction.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Alphaproteobacteria / enzymology*
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Binding Sites / genetics
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Catalysis
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Cloning, Molecular
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Crystallography, X-Ray
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Dimerization
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Escherichia coli / genetics
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Flavin-Adenine Dinucleotide / chemistry
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Flavin-Adenine Dinucleotide / metabolism
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Histidine / chemistry
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Hydrogen Bonding
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Ligands
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Mixed Function Oxygenases / chemistry*
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Mixed Function Oxygenases / genetics
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Mixed Function Oxygenases / metabolism*
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Models, Molecular
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Nicotinic Acids / chemistry*
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Nicotinic Acids / genetics
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Nicotinic Acids / isolation & purification
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Nicotinic Acids / metabolism*
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Oxidation-Reduction
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Protein Binding / genetics
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Protein Structure, Secondary
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Recombinant Proteins / analysis
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Recombinant Proteins / chemistry
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Recombinant Proteins / isolation & purification
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Recombinant Proteins / metabolism
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Substrate Specificity / genetics
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Ultracentrifugation
Substances
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2-methyl-3-hydroxypyridine-5-carboxylic acid
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Ligands
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Nicotinic Acids
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Recombinant Proteins
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Flavin-Adenine Dinucleotide
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Histidine
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Mixed Function Oxygenases