Trypsin-susceptible cell surface characteristics of Streptococcus sanguis

The adherence of Streptococcus sanguis to saliva-coated hydroxylapatite was markedly reduced by treatment of the cells with trypsin. In Scatchard plots of adherence data, protease-treated S. sanguis did not exhibit the characteristic positive slopes, suggesting that trypsin prevented cooperative interactions between the cells and artificial pellicle. Trypsin also reduced the tendency of S. sanguis to bind to hexadecane and to octyl-Sepharose. When sodium dodecyl sulfate was used to elute S. sanguis from columns of octyl-Sepharose, it was observed that the elution profiles of trypsin-treated cells were more complex than those of control cells. Water and salts were incapable of removing the cells from octyl-Sepharose. The results suggest that adherence to saliva-coated hydroxylapatite, binding to hexadecane and to octyl-Sepharose depend on trypsin-susceptible cell surface molecules.