Main muropeptides from LGG PG digested with or without Msp1.

aPeak numbers refer to Figure 5 and Figure S1. bDi, disaccharide dipeptide (L-Ala-D-iGln); Tri, disaccharide tripeptide (L-Ala-D-iGln-L-Lys); Tetra, disaccharide tetrapeptide (L-Ala-D-iGln-L-Lys-D-Ala); Disaccharide, GlcNAc-MurNAc; Ac, acetylation, iGln, isoglutamine; N, D-Asn; A, D-Ala; K, L-Lys. cSodiated molecular ions were the most abundant ones on MALDI-TOF mass spectra for all muropeptides. dPercentage of each peak was calculated as the ratio of the peak area over the sum of areas of all the peaks identified in the corresponding chromatogram (see Figure 5). eND, non detected.