RP-HPLC profiles of cell walls of strains COL and the conditional mutant.

<p>(<b>A</b>) RP-HPLC profiles of cell walls prepared from strains COL and COL<i>pCadmurT-gatD</i> mutant grown with and without 0.2 µM of CdCl₂. The cell walls were purified and digested with cellosyl and lysostaphin and the resulting muropeptides were reduced and analyzed by RP-HPLC. Fractions eluting at 50.73 min (peak I), 52.42 min (peak II), 54.10 min (peak III), 56.13 min (peak IV) in COL strain, and eluting at 47.00 min (peak V) and 48.33 min (peak VI) in COL<i>pCadmurT-gatD</i>, grown without the inducer, were collected and analyzed by mass spectrometry. (<b>B</b>) Proposed structures for the muropeptides corresponding to peaks I, II, III, IV, V and VI. Structures with different numbers of glycine residues associated with the D-Ala and L-Lys of the stem peptide, were identified for each peak. The mass of the analyzed compounds are presented in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002508#ppat-1002508-t002" target="_blank">Table 2</a>.