Abstract
Bacteria in a biofilm are enmeshed in a self-synthesized extracellular polysaccharide matrix (PGA), which is a linear polymer of beta(1,6)-linked N-acetylglucosamine (GlcNAc) residues. Dispersin B (DspB), a soluble glycoside hydrolase produced by the periodontal pathogen Actinobacillus actinomycetemcomitans degrades PGA. The enzyme DspB is an alpha/beta TIM-barrel protein and belongs to family 20 glycosyl hydrolases members. The enzyme activity of DspB with regard to its substrate specificity towards beta(1,6)-linked GlcNAc polymers and its endo/exo character was investigated through ligand docking and the hydrolysis of synthetic oligosaccharides. Ligand docking analysis suggested that beta(1,6)-linked GlcNAc oligosaccharide bound to the active site better that beta(1,4)-linked GlcNAc oligosaccharide. Our combined results indicate that DspB is an exo-acting enzyme that hydrolyzes beta(1,6)-linked N-acetylglucosamine oligomers.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Aggregatibacter actinomycetemcomitans / enzymology
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Aggregatibacter actinomycetemcomitans / genetics
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Amino Acid Sequence
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Bacterial Proteins / chemistry*
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism
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Bacterial Proteins / pharmacology*
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Biofilms / drug effects*
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Carbohydrate Sequence
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Catalytic Domain
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Escherichia coli / metabolism
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Glycoside Hydrolases / chemistry*
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Glycoside Hydrolases / genetics
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Glycoside Hydrolases / metabolism
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Glycoside Hydrolases / pharmacology*
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Hydrolysis
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Ligands
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Models, Molecular
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Molecular Sequence Data
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Oligosaccharides / chemistry
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Oligosaccharides / metabolism
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Polysaccharides, Bacterial / chemistry
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Polysaccharides, Bacterial / metabolism
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Sequence Homology, Amino Acid
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Substrate Specificity
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Thermodynamics
Substances
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Bacterial Proteins
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Ligands
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Oligosaccharides
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Polysaccharides, Bacterial
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Glycoside Hydrolases
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dispersin B, Actinobacillus actinomycetemcomitans