Team:Grinnell/Project/DspB

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Revision as of 18:50, 6 July 2011

DspB is most likely an N-acetylglucosaminidase that causes the detachment of cells from biofilm colonies through the 1→ 4 glycosidic bond of β-substituted N-acetylglucosamine (3). DspB is homologous to family 20 glycosyl hydrolases which cleave terminal monosaccharide residues (Kaplan 2003).One possible substrate for dspB is a type IV pilus required for the attachment and autoaggregation of bacteria by altering its adhesive properties. Another possible substrate is exopolysaccharide which is part of the exopolysaccharide matrix which plays a role in biofilm formation. Exopolysaccharides may contain N-acetylglucosamine which dspB is thought to hydrolyze. Manuel et al have characterized the mechanistic aspects of DspB and show that conserved D183 and E184 resemble the proposed 20 β-hexosaminidase mechanism; that aromatic residues W237, Y278 and D183 assist N-acetal group orientation and hydrolysis; that Y187 plays a role in specificity; and that residues R27, E332 and W330 help stabilize the transition state of hydrolysis. Although studies on DspB have used Actinobacillus actinomycetemcomitans as a study subject, the fact that DspB has been isolated and purified and has been shown to increase dissemination of wild type cells and restore dissemination in mutant cells indicates that it can be applied to other biofilm forming organisms.

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-	DspB is most likely an N-acetylglucosaminidase that causes the detachment of cells from biofilm colonies through the 1→ 4 glycosidic bond of β-substituted N-acetylglucosamine (3). DspB is homologous to family 20 glycosyl hydrolases which cleave terminal monosaccharide residues (Kaplan 2003).One possible substrate for dspB is a type IV pilus required for the attachment and autoaggregation of bacteria by altering its adhesive properties. Another possible substrate is exopolysaccharide which is part of the exopolysaccharide matrix which plays a role in biofilm formation. Exopolysaccharides may contain N-acetylglucosamine which dspB is thought to hydrolyze. Manuel et al have characterized the mechanistic aspects of DspB and show that conserved D183 and E184 resemble the proposed 20 β-hexosaminidase mechanism; that aromatic residues W237, Y278 and D183 assist N-acetal group orientation and hydrolysis; that Y187 plays a role in specificity; and that residues R27, E332 and W330 help stabilize the transition state of hydrolysis. Although studies on DspB have used Actinobacillus actinomycetemcomitans as a study subject, the fact that DspB has been isolated and purified and has been shown to increase dissemination of wild type cells and restore dissemination in mutant cells indicates that it can be applied to other biofilm forming organisms.	+
		+	DspB is most likely an N-acetylglucosaminidase that causes the detachment of cells from biofilm colonies through the 1→ 4 glycosidic bond of β-substituted N-acetylglucosamine (3). DspB is homologous to family 20 glycosyl hydrolases which cleave terminal monosaccharide residues (Kaplan 2003).One possible substrate for dspB is a type IV pilus required for the attachment and autoaggregation of bacteria by altering its adhesive properties. Another possible substrate is exopolysaccharide which is part of the exopolysaccharide matrix which plays a role in biofilm formation. Exopolysaccharides may contain N-acetylglucosamine which dspB is thought to hydrolyze. Manuel et al have characterized the mechanistic aspects of DspB and show that conserved D183 and E184 resemble the proposed 20 β-hexosaminidase mechanism; that aromatic residues W237, Y278 and D183 assist N-acetal group orientation and hydrolysis; that Y187 plays a role in specificity; and that residues R27, E332 and W330 help stabilize the transition state of hydrolysis. Although studies on DspB have used Actinobacillus actinomycetemcomitans as a study subject, the fact that DspB has been isolated and purified and has been shown to increase dissemination of wild type cells and restore dissemination in mutant cells indicates that it can be applied to other biofilm forming organisms.