FIG. 2.

SAR in the ring linker moiety. (A) Structures of a series of ring linker-substituted analogues used in this study. Dpr, diaminopropionic acid; Hse, homoserine. (B) GBAP agonist activity of the ring linker-substituted analogues. E. faecalis OU510 was cultured for 5 h in the presence of 10 nM each synthetic peptide, and the induced gelatinase activity in the culture supernatant was measured as GBAP agonist activity by azocoll assay according to a previously described protocol (20, 26). The activity of 10 nM GBAP (black bar) was determined to normalize the agonist activity of each peptide. The averages ± standard deviations of duplicate determinations are presented. (C) GBAP agonist/antagonist activity of disulfide-GBAP and M¹¹A-GBAP. Activity higher than 100% means agonist activity, and activity lower than 100% means antagonist activity. E. faecalis OG1RF was cultured for 5 h in the presence of various concentrations of each synthetic peptide. For the control, the induced gelatinase activity was measured in the strain cultured without the addition of exogenous peptide (black bar) and was used to normalize the agonist/antagonist activity of each peptide. The induced gelatinase activity in the culture supernatant was measured by azocoll assay. The averages ± standard deviations of duplicate determinations are presented.