Extended Data Fig. 2: Muropeptide analysis identifies a tetrasaccharide- monopeptide.
a, Schematic of sacculi isolation and mutanolysin/NaBH4 treatment to generate muropeptides for LC-MS analysis. b, Total ion chromatograms comparing the muropeptide species isolated from WT vs. ∆lytH sacculi. Muropeptide species eluted between 12-18 min using this analytical method. The XCMS online platform was used to identify species that were enriched or depleted between the two strains. c, The tetrasaccharide-monopeptide species was enriched in sacculi isolated from cells expressing lytHWT. A chemical structure consistent with this species, based on an [M + 2] ion with experimental m/z = 866.3881, is shown. d, The [M + 2] ion was targeted for fragmentation to confirm the species was a tetrasaccharide-monopeptide. e, The theoretical and experimental isotope distributions for the tetrasaccharide- monopeptide species are shown.
