Table 1. Stem peptide composition of select S. pneumoniae strains. a .
| Peak | Peptide characteristics | wt b | ΔmurMN | malM-murMN | murMN TIGR4 c | murMN R36A c | murMN Pen6 c | |
|---|---|---|---|---|---|---|---|---|
| 1 | Linear | Monomer | 20.8 (0.31) | 23.7 (0.97) | 11.8 (0.20) | 20 (1.01) | 20.6 (0.38) | 6.9 (0.41) |
| 2 | Linear | Monomer | 4.1 (0.09) | 1.6 (0.11) | 7.1 (0.36) | 4.8 (0.95) | 2.9 (0.16) | 9.9 (0.65) |
| 3 | Branched | Monomer | 2.3 (0.14) | 0 | 10.6 (0.17) | 2.8 (0.76) | 2.9 (0) | 7 (1.51) |
| I | Branched | Monomer | 0.9 (0.16) | 0 | 3.0 (0.29) | 1.1 (0.53) | 1.4 (0) | 6.2 (1.22) |
| 4 | Linear | Dimer | 24.7 (0.21) | 57.2 (1.48) | 5.2 (0.03) | 21.6 (1.15) | 30.7 (0.30) | 2 (0.28) |
| 5 | Branched | Dimer | 15 (0.04) | 4.8 (0.16) | 12.8 (0.43) | 15.3 (1.44) | 12.9 (0.26) | 4.4 (0.17) |
| 6a | Branched | Dimer | 3.9 (0.10) | 1.1 (1.59) | 4 (0.22) | 3.7 (0.45) | 3.5 (0.12) | 1.1 (0.05) |
| 6b | Branched | Dimer | 7.7 (0.10) | 1.3 (1.9) | 5.8 (0.10) | 8.1 (0.37) | 6.7 (0.10) | 5.5 (0.22) |
| 7 | Branched | Dimer | 4.3 (0.02) | 0 | 17 (0.75) | 5.5 (0.47) | 2.9 (0.04) | 12.5 (0.29) |
| 10 | Linear | Trimer | 2.9 (0) | 8.3 (0.40) | 0.8 (0.51) | 2.6 (0.16) | 3.7 (0.01) | 1.6 (0.15) |
| IV | Branched | Dimer | 1.8 (0.04) | 0 | 5.6 (0.15) | 2.3 (0.09) | 1.5 (0.03) | 10.9 (0.03) |
| V | Branched | Dimer | 2.5 (0.04) | 0.6 (0.88) | 7.5 (0.10) | 3.3 (0.12) | 2.2 (0.03) | 14.5 (0.29) |
| 8 | Branched | Trimer | 4.6 (0.01) | 0 | 2.7 (0.09) | 4 (0.69) | 4.5 (0.06) | 1.4 (0.09) |
| VI | Branched | Dimer | 1.3 (0.09) | 0.7 (0.95) | 2.6 (0.06) | 1.7 (0.03) | 1.4 (0.08) | 14.7 (1.83) |
| 9 | Branched | Trimer | 3.1 (0.08) | 0.5 (0.76) | 3.4 (0.37) | 3.3 (0.23) | 2.3 (0.07) | 1.2 (0.06) |
| Total | 100 | 100 | 100 | 100 | 100 | 100 | ||
| Branched peptides (%) | 47.6 (0.01) | 9.1 (2.74) | 75.1 (0.69) | 51.1 (0.65) | 42.0 (0.07) | 79.6 (0.10) | ||
| Monomers | 28.1 (0.08) | 25.4 (0.85) | 32.6 (0.61) | 28.7 (0.68) | 27.8 (0.22) | 30.0 (2.49) | ||
| Branched monomers (%) | 11.6 (1.03) | 0 | 42.0 (0.63) | 13.7 (4.80) | 15.2 (0.14) | 43.9 (5.45) | ||
| Oligomers | 71.9 (0.08) | 74.6 (0.85) | 67.4 (0.61) | 71.3 (0.68) | 72.2 (0.22) | 70.0 (2.49) | ||
| Branched oligomers (%) | 61.7 (0.33) | 12.2 (3.53) | 91.1 (0.89) | 66.2 (1.52) | 52.3 (0.26) | 94.8 (0.38) | ||
| Crossbridged oligomers d (%) | 50.9 (0.48) | 10.4 (1.01) | 82.5 (1.11) | 54.8 (1.93) | 43.1 (0.37) | 86.9 (0.34) | ||
a Each peak corresponds to a specific peptide structure as depicted in S4 Fig. Values represent the mean abundance of the indicated species relative to the total amount of peptide material analyzed and numbers within parentheses denote the standard deviation of two independent experiments.
b TIGR4 strain
c The murMN coding regions and intervening sequence from each strain (TIGR4, R36A, Pen6) were introduced into ΔmurMN, replacing the chloramphenicol resistance marker at the native chromosomal locus
d A crossbridge is defined as a crosslink that directly incorporates the branch structure (covalent linkage between alanine from branch and fourth position alanine of adjacent peptide)