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. 2004 Jun;186(11):3415–3422. doi: 10.1128/JB.186.11.3415-3422.2004

TABLE 2.

Molecular mass and structure of muropeptides from C. innocuum NCIB 10476

Peak Muropeptide type Alanine no.a Proposed structureb m/zc
Observed Calculated
1 Monomer DS-mono 570.2 570.2
2 Monomer DS-di 698.3 698.4
3 Monomer DS-tetra 897.4 897.6
4 Monomer DS-A2-trid 968.5 968.7
5 Monomer DS-tetra(−42) 855.4 855.7
6 Monomer DS-A-tetra 968.5 968.5
7 Monomer DS-A-tetra(OH)d 969.5 969.7
8 Monomer DS-penta[A](−42) 926.6 926.6
Monomer DS-A2-penta[S](OH)d 1,127.5 1,128.0
9 Monomer DS-A2-tri(−42) 926.5 926.7
Monomer DS-A2-penta[S] 1,126.5 1,127.2
10 Monomer DS-A-tetra(OH)(−42) 927.4 927.6
11 Monomer DS-A2-tetra 1,039.8 1,039.8
12 Monomer DS-A2-penta[S](OH)(−42) 1,085.5 1,085.4
13 Monomer DS-A-tetra(−42) 926.5 926.8
14 Monomer DS-A2-penta[S](−42)d 1,084.5 1,084.8
Monomer DS-A2-penta[A](OH)d 1,111.5 1,111.5
15 Monomer DS-A2-tetra(−42) 997.7 998.4
16 Dimer [3] BisDSe 1,917.9 1,918.2
17 Dimer [4] BisDSe 1,990.0 1,990.1
Dimer [3] DS-A2-tetra-A-penta[S](OH)(−42)f 2,035.0 2,034.7
18 Dimer [4] BisDS-A2-tetra-A2-penta[S] 2,148.0 2,148.3
19 Dimer [3] BisDS—(OH)(−42) 1,876.9 1,877.0
20 Dimer [4] BisDS-A2-tetra-A2-tri(−42)d 1,947.9 1,947.8
21 Dimer [4] BisDS—(−42)e 1,947.9 1,947.0
22 Dimer [4] BisDS-A2-tetra-A2-penta[S](OH)(−42) 2,105.0 2,105.0
23 Dimer [4] BisDS-A2-tetra-A2-penta[S](OH × 2)(−42) 2,106.0 2,105.7
24 Trimer [6] TerDS—(OH)e 3,010.5 3,010.9
25 Trimer [4] TerDS-A2-tetra-A-tetra-A-penta[S](OH × 3)f 3,028.5 3,028.3
26 Dimer [4] BisDS-A2-tetra-A2-tri(OH)(−42 × 2)d 1,905.9 1,905.9
Dimer [3] BisDS—(−42 × 2)e 1,833.9 1,833.2
27 Dimer [4] BisDS—(OH)(−42 × 2) 1,905.9 1,906.2
28 Dimer [4] BisDS-A2-tetra-A2-penta[S](OH × 2)(−42 × 2) 2,064.9 2,065.3
29 Trimer [6] TerDS-tetra-tetra-tri (OH) (−42)e 2,969.4 2,968.9
a

Data in brackets are total number of alanines present in the cross-bridge, in the free N- terminal and C-terminal ends of oligomers.

b

Proposed structure deduced from the molecular mass or MS/MS. DS, disaccharide (GlcNAC-MurNAC); BisDS, dimeric form; TerDS, trimeric form; mono, monopeptide (l-Ala); di, dipeptide (l-Ala-d-iGln); tri, tripeptide (l-Ala-d-iGln-l-Lys); tetra, tetrapeptide (l-Ala-d-iGln-l-Lys-d-Ala); penta [A], pentapeptide (l-Ala-d-iGln-l-Lys-d-Ala-d-Ala); penta [S], pentapeptide (l-Ala-d-iGln-l-Lys-d-Ala-d-Ser); A, one alanine branched on l-Lys; A2, two alanines branched on L-Lys; OH indicates the presence of Glu instead of iGln; (−42), monomer without acetyl group on GlcNAC, (−42 × 2), dimer without acetyl group on both GlcNAC of the dimer. For other trimers, tetramers, and pentamers (peaks >29), no structure is proposed.

c

(M + H)+ ion of the reduced muropeptide.

d

Structure determined after MS/MS.

e

No structure is proposed, due to the unknown distribution of the alanine(s) (see footnote a) in the interpeptide bridge or at the C terminus: for a dimer it can be either a BisDS-tetra-tetra or a BisDS-tetra-tri, and for a trimer it can be either a TerDS-tetra-tetra-tetra or a TerDS-tetra-tetra-tri.

f

Assignment of the number of alanine in the cross bridge is arbitrary.