Figure 2.

Activity of SpLdcB and BsLdcB against Peptidoglycan and Peptides

(A) HPLC chromatograms of muropeptides from S. pneumoniae strains, obtained after incubating PG with or without SpLdcB or SpLdcB(E204A) in the presence of Zn²⁺ or EDTA, followed by digestion with cellosyl and reduction with sodium borohydride. The muropeptides are: Tri, GlcNAc—MurNAc(r)—L-Ala—D-γ-Gln—L-Lys; Tetra, GlcNAc—MurNAc(r)—L-Ala—D-γ-Gln—L-Lys-D-Ala; TetraTri, GlcNAc—MurNAc—L-Ala—D-γ-Gln—L-Lys—D-Ala—L-Lys—D-γ-Gln—L-Ala—MurNAc(r)—GlcNAc; TetraTetra, GlcNAc—MurNAc—L-Ala—D-γ-Gln—L-Lys—(D-Ala)—D-Ala—L-Lys—D-γ-Gln—L-Ala—MurNAc(r)—GlcNAc; deAc, deacetylation at GlcNAc; SA, L-Ser—L-Ala branch (at L-Lys). GlcNAc, N-acetylglusosamine; MurNAc(r), N-acetylmuramitol.

(B) HPLC chromatograms of muropeptides from B. subtilis strains, obtained after incubating PG with or without BsLdcB, followed by digestion with cellosyl and reduction with sodium borohydride. Muropeptides: Tri, GlcNAc—MurNAc(r)—L-Ala—D-γ-Glu—meso-Dap(NH₂); Tetra, GlcNAc—MurNAc(r)—L-Ala—D-γ-Glu—meso-Dap(NH₂)—D-Ala; TetraTri, GlcNAc—MurNAc—L-Ala—D-γ-Glu—meso-Dap(NH₂)—D-Ala-meso-Dap(NH₂)— D-γ-Glu—L-Ala—MurNAc(r)—GlcNAc; TetraTetra, GlcNAc—MurNAc—L-Ala—D-γ-Glu—meso-Dap(NH₂)—(D-Ala)—D-Ala—meso-Dap(NH₂)— D-γ-Glu—L-Ala—MurNAc(r)—GlcNAc; meso-Dap(NH₂), meso-diaminopimelic acid (amidated).

(C) TLC of SpLdcB incubated with various substrates.