Sialic acids protein conformation, effect

According to Rolla, ionic bonds are important in the associations between bacterial polysaccharides and protein-coated tooth surfaces (21). This was based on in vitro experiments on the afiinity of dextran for hydroxyapatite powder coated with salivary glycoprotein specifically, adsorption of dextran was inhibited by 0.5M. Prior treatment of the coated hydroxyapatite with neuraminidase also reduced adsorption of dextran. Neuraminidase would be expected to reduce the negative charge of the protein coat by removing ionized sialic acid moieties. Of course, reduced adsorption of dextran could result from conformational changes induced in the pellicle protein by the neuraminidase treatment, as was apparently effected by 4M or 8M urea, in other experiments. 

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