FIGURE 9.

Hypothetical model for bacteria-gp340 interactions. Viridans streptococci utilize the AgI/II adhesin to bind the VEVLXXXXW-epitope on gp340. In addition to AgI/II family polypeptides, some streptococci express carbohydrate-binding adhesins, like the sialic acid-binding adhesin Hsa or GspB of S. gordonii and pili proteins in S. pyogenes. The SRCR epitope, devoid of XXXXW and possibly utilizing the RX(R/Q)XR motif, is involved in recognition of conserved leucine-rich repeats in different bacterial surface proteins.