HPLC elution profile of <i>C. jejuni</i> muropeptides and proposed muropeptide structures.

<p>Purified PG was digested with cellosyl and the resulting muropeptides were reduced with sodium borohydride and separated on a Prontosil 120-3-C18 AQ reverse-phase column. HPLC profiles are shown for <b>A, </b><i>C. jejuni</i> wild-type 81-176; <b>B,</b> Δ<i>pgp1</i>; <b>C,</b> the complement Δ<i>pgp1</i>c; <b>D,</b> the <i>pgp1</i> overexpressing strain, 81-176+<i>pgp1</i>. Peak numbers correspond to the main muropeptide peak fractions of <i>C. jejuni</i> 81-176 analyzed by LTQ-FT-MS (<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002602#ppat.1002602.s005" target="_blank">Table S3</a>) to determine the structures shown in <b>E</b>. G, N-acetylglucosamine; M, reduced N-acetylmuramic acid; L-Ala, L-alanine; D-iGlu, D-isoglutamic acid; D-Glu, D-glutamic acid; <i>meso-</i>DAP, <i>meso-</i>diaminopimelic acid; Gly. Glycine; Ac, O-acetyl groups at the C-6 hydroxyl group of MurNAc; Anh, 1,6-anhydro group at MurNAc. The asterisk (*) indicates that it is not known on which MurNAc residue the modification occurs.