Inhibition of Streptococcus mutans glucosyltransferase activity by antiserum to a subsequence peptide.

An antigenic 15-amino-acid peptide sequence (gtfB.1) from the glucosyltransferase B enzyme of the cariogenic bacterium Streptococcus mutans GS-5 was identified previously from the genetic fusion of this sequence to the B subunit of cholera toxin. The resulting chimeric protein was used to raise antiserum in rabbits. This antiserum was shown to recognize the native glucosyltransferase enzyme and to inhibit its activity. The antiserum inhibited the synthesis of water-soluble glucan by approximately 40% and the synthesis of water-insoluble glucan by greater than 90%. The antiserum was shown to partially inhibit fructosyltransferase activity as well. The ability of this antipeptide antiserum to inhibit several enzymes from S. mutans suggests that these enzymes share an epitope related to enzymatic activity.