TABLE 2.
Molecular mass and composition of the muropeptides of S. pneumoniae R6 and transformant R6T3-CCP after separation by HPLC
| Peak no.a | Structureb |
Mr
|
Size of peak/ total size of all peaks (%)
|
||
|---|---|---|---|---|---|
| Observed | Calculated | R6 | R6T3CCP | ||
| 1 | DS-tri | 825.4 | 825.3 | 19.01 | 20.81 |
| 2 | DS-tri(OH) | 826.4 | 826.3 | 3.18 | 3.28 |
| 3 | DS-tri(−42) | 783.4 | 783.3 | 12.44 | 15.11 |
| 4 | DS-tri(OH)(−42) | 784.4 | 784.3 | 3.15 | 4.40 |
| 5 | DS-tetra | 897.2 | 896.4 | 2.67 | 1.18 |
| 6 | DS-S-tri | 912.2 | 912.4 | 0.81 | 1.03 |
| 7 | DS-penta | 967.4 | 967.3 | 4.75 | 3.52 |
| 8 | DS-A-S-tri | 983.6 | 983.5 | 7.70 | 7.12 |
| 9 | DS-penta(−42) | 925.7 | 925.5 | 0.92 | 0.60 |
| 10 | DS-A-A-tri | 967.6 | 967.5 | 1.38 | 1.63 |
| 11 | DS-A-S-tri(−42) | 941.6 | 941.2 | 5.16 | 6.21 |
| 12 | DS-A-S-tri(OH)(−42) | 942.5 | 942.2 | 1.62 | 1.73 |
| 12* | DS-A-A-tri(−42) | 925.8 | 925.5 | 0 | 1.96 |
| 13 | BisDS-tetra-tri | 1704.4 | 1703.8 | 6.65 | 2.46 |
| 14 | BisDS-tetra-A-S-tri | 1862.7 | 1862 | 6.1 | 4.13 |
| 15 | BisDS-A-S-tetra-tri | 1862.8 | 1862 | 1.66 | 1.15 |
| 16 | BisDS-tetra-tri(−42) | 1662.6 | 1662.9 | 3.05 | 3.16 |
| 17 | BisDS-A-S-tetra-A-S-tri | 2020.4 | 2020.1 | 2.58 | 2.15 |
| BisDS-A-A-tetra-A-S-tri | 2004.3 | 2004.1 | |||
| 18 | BisDS-tetra-A-S-tri(−42) | 1820 | 1820 | 2.21 | 2.72 |
| 19 | BisDS-A-S-tetra-tri(−42) | 1820.8 | 1820.1 | 2.71 | 3.46 |
| 20 | BisDS-A-A-tetra-A-S-tri(OH) | 2005.2 | 2005.1 | 1.80 | 1.26 |
| 21 | BisDS-tetra-tri(−42x2) | 1620.5 | 1619.7 | 4.54 | 2.89 |
| 22 | BisDS-tetra-A-A-tri(−42) | 1804.8 | 1804.8 | 1.62 | 2.47 |
| 23 | BisDS-A-S-tetra-A-S-tri(−42) | 1978.6 | 1978.1 | 2.31 | 2.50 |
| 24 | BisDS-tetra-A-S-tri(−42x2) | 1778.2 | 1777.9 | 1.98 | 3.07 |
Peaks are shown in Fig. 6.
DS, disaccharide (GlcNAc-MurNAc); bis, dimeric form; tri, tripeptide (l-Ala-d-Gln-l-Lys); tetra, tetrapeptide (l-Ala-d-Gln-l-Lys-d-Ala); penta, pentapeptide (l-Ala-d-Gln-l-Lys-d-Ala-d-Ala). OH indicates the presence of Glu instead of Gln. S, serine; A-A, Ala-Ala; A-S, Ala-Ser; these amino acids are branched to the ɛ amino group of the Lys residue and are also present in the interpeptide bridge. Peak 17 contained two compounds as described which could not be separated. −42, the mass that was obtained after cleavage of an acetyl radical from the GlcNAc moiety of the DS during preparation of the peptidoglycan; −42x2, two acetyl radicals were missing, one on each DS of the dimer.