TABLE 5.

Peptidoglycan composition of cpxA24 and isogenic ygaU, ldtD, and ygaU ldtD strains

^aThe molar ratios of the different muropeptide structures were calculated for a cpxA24 mutant or isogenic derivatives carrying ygaU::kan, ldtD::kan, or ΔldtD and ygaU::kan alleles, as previously described (26). All strains were grown at 30°C. The different muropeptide structures are abbreviated according to length, where M indicates a monomer, D indicates a cross-linked dimer, and T indicates a cross-linked trimer. The numbers indicate the length of the stem peptide, and the last letter indicates whether the muropeptide contains a DAP-DAP cross-link (D) or is anchored to Braun's lipoprotein (L) or if there is a 1,6-anhydro-muramic acid residue (N) or a glycine (G) at the end of the stem peptide. D-D/total is the ratio of DAP-DAP cross-links to the total cross-links. The averages of data from three measurements from biological replicates are shown. Shading indicates measurements that were different from the cpxA24 value by 25%.

^bThe average muropeptide composition for the cpxA24 mutant was determined once and is indicated here and in Table 3 (see also Table S1 in the supplemental material).