Muropeptide composition analysis of Bifidobacterium breve strains.
(a) Schematic representation of the two possible cross-linking types in the PGN of B. breve: Ddt-mediated 4-3 cross-link and Ldt-mediated 3-3 cross-link. Donor peptide stems are labeled in red. The arrow indicates the direction of cross-links catalyzed by transpeptidases. (b) Base peak chromatograms of muropeptide analysis of B. breve ATCC 15700, CSCC 1900, and ATCC 15698 strains. The main peaks were annotated with muropeptide symbols. (c) Heatmap showing the muropeptide compositions (% of total) of the PGN of three B. breve strains. Symbols: M, monomer; D, dimer; T, trimer (numbers following the letters indicate the number of amino acids in stem peptides). M0, disaccharide; M1, disaccharide-monopeptide; M2, disaccharide-dipeptide; M4, disaccharide-tetrapeptide; M3b, disaccharide-tripeptide with an interpeptide bridge; M3Nb, disaccharide-tripeptide with an anhydro-MurNAc and an interpeptide bridge; M4b, disaccharide-tetrapeptide with an interpeptide bridge; M4Nb, disaccharide-tetrapeptide with an anhydro-MurNAc and an interpeptide bridge; M5b, disaccharide-pentapeptide with an interpeptide bridge; D34, disaccharide-tripeptide–disaccharide-tetrapeptide with a peptide cross-link; D34N, disaccharide-tripeptide–disaccharide-tetrapeptide with a peptide cross-link and an anhydro-MurNAc; D44, disaccharide-tetrapeptide–disaccharide-tetrapeptide with a peptide cross-link; D44N, disaccharide-tetrapeptide–disaccharide-tetrapeptide with a peptide cross-link and an anhydro-MurNAc; D45, disaccharide-tetrapeptide–disaccharide-pentapeptide with a peptide cross-link; T335, disaccharide-tripeptide–disaccharide-tripeptide-disaccharide-pentapeptide with two peptide cross-links; T444, disaccharide-tetrapeptide–disaccharide-tetrapeptide-disaccharide-tetratapeptide with two peptide cross-links; T445, disaccharide-tetrapeptide–disaccharide-tetrapeptide-disaccharide-pentapeptide with two peptide cross-links.
Figure 4 Source data 1
Heatmap data of Figure 4c.