The surface protein of the Streptococcus mutans（S. mutans） is the important adhesins of the strains cell wall. It has been shown to mediate the adherence of S. mutans to the teeth directly and contribute to the agglutination of the bacterium. The C terminus of the surface protein is highly conserving and adhesining. And the human IgG- cross- reacting domain and the T, B cell antigenic epitopes are in the domains too. In addition, the Sortase enzyme in the C terminus domain is responsible for anchoring the surface protein to the cell surface and plays an important role in cariogenicity of S. mutans.
