FIG 5.

Putative protease activity is not required for LsrS activity. (A) Proposed transmembrane topology of LsrS. The hydrophobicity plots predicted from the TopPred2, TMpred, and TMHMM algorithms are similar. The predicted six putative transmembrane α helices are indicated. The positions (residues) for LacZ fusions are shown. The residues with a dark background are putative active sites for CAAX protease activity. (B and C) Site-directed mutations in the conserved active-site motifs do not affect LsrS receptor function in S. pyogenes (B) or S. mutans (C). Deferred antagonism assays were repeated at least three times, and representative areas of the plates are shown.