Figure 6. Activity of the epipeptides on Bacillus subtilis.

(a) Growth of B. subtilis in liquid LB medium in the presence of YydF_18-49 or peptides containing one or two epimerized residues in position 36 and 44. B. subtilis was grown in LB medium alone (black squares), in the presence of YydF_18-49 (white squares), YydF_a (purple squares), YydF_c (Green squares) or YydF_b (red squares). Each measurement is the mean of three growth experiments with the SD indicated. (b) Growth of B. subtilis in the presence of YydF_18-49 at initial time or mid-exponential phase. B. subtilis was grown in LB medium alone (black squares), in the presence of YydF_18-49 (white squares), YydF_b (red squares) or after addition of YydF_b at mid-exponential phase (indicated by the red arrow) (light blue squares). Each measurement is the mean of three growth experiments with the SD indicated. (c) LC-MS/MS analysis of the purified peptide from B. subtilis. (see Supplementary methods for peptide purification). (d) LC-MS analysis of YydF_33-49, YydF_33-49DD synthetic peptides (traces 1&2) and the peptide isolated from B. subtilis (trace 3). (See Supplementary Fig. S28 & S29 for complete assignment). (e) Growth of B. subtilis in liquid LB medium in the presence of YydF_33-49DD. B. subtilis was grown in LB medium alone (black squares), in the presence of YydF_33-49 (white squares) or YydF_33-49DD (red squares). Each measurement is the mean of three growth experiments with the SD indicated. Growth ratio of B. subtilis in the presence of (f) YydF_18-49 (100 µM) or YydF_b and (g) YydF_33-49 or YydF_33-49DD. Ratios were determined by comparison with growth in the absence of peptide.