Fig. 2: The peptidoglycan hydrolytic ability is required and sufficient for LPH’s colitis protective effects.

a Schematic of LPH’s sequence organization: yellow represents the signal sequence; blue represents the conserved 3D-domain. The predicted active site residues are typed in red. b A summarization of proteins with the 3D-domain. c The ability of LPH or LPH-3D to hydrolyze remazol-dyed peptidoglycan was measured by optical density (n = 4 per group), data are representative of 2 independent experiments. d–h The protective effects of LPH or LPH-3D on TNBS-induced colitis, n = 6 (female) per group: body weight loss (d); representative H&E staining of colonic tissue, scale bar, 200 μm (e); the semiquantitative scoring of inflammation (f); colon length (g) and serum FITC-dextran level (h); i–m Protective effects of peptidoglycan digests of BSA (BSA_PG), LPH (LPH_PG), or LPH-3D (LPH-3D_PG) on TNBS-induced colitis, n = 6 (female) per group: body weight loss (i); representative H&E staining of colonic tissue, scale bar, 200 μm (j); the semiquantitative scoring of inflammation (k); colon length (l) and serum FITC-dextran level (m). BSA: bovine serum albumin; LPH-3D: the 3D-domain truncation of LPH; PG: peptidoglycan from S. aureus. Data are representative of 3 independent experiments and presented as mean ± SD. Each dot indicates an individual mouse. Statistical analyses were performed using one-way ANOVA with Bonferroni post hoc test (c, f, g, h, k, l, m), repeated measures ANOVA with Bonferroni post hoc test (d, i). Source data are provided as a Source data file.