TABLE 1.

Calculated and observed m/z values for protonated, sodiated, and deprotonated molecular ions of vegetative cell wall muropeptides

Muropeptidea	Ion	m/z		Δm (Da)b	Muropeptide composition
		Observed	Calculated		Glcc	Murd	Ala	Glu	A2pm	Gly
1	[M + Na]+	892.7	893.9	−1.1	1	1	1	1	1	0
	[M − H]−	868.8	869.9	−1.2
2	[M + Na]+	972.6	893.9	78.5	1	1	1	1	1	0
	[M − H]−	948.0	869.9	78.5
3	[M + H]+	870.3	871.9	−1.6	1	1	1	1	1	0
	[M − H]−	868.1	869.9	−1.8
4	[M + H]+	829.1	871.9	−42.8	1	1	1	1	1	0
	[M − H]−	827.1	869.9	−42.8
5	[M + H]+	699.8	699.7	0.1	1	1	1	1	0	0
	[M − H]−	698.2	697.7	0.5
6	[M + H]+	941.7	942.9	1.2	1	1	2	1	2	0
	[M − H]−	940.2	940.9	0.7
7	[M + Na]+	1,136.9	1,137.0	0.1	1	1	2	1	1	0
	[M − H]−	1,112.9	1,113.0	0.1
8	[M + Na]+	1,136.4	1,137.0	−0.6	1	1	2	1	2	0
	[M − H]−	1,111.9	1,113.0	−1.1
9	[M + Na]+	1,022.3	1,021.9	0.4	1	1	2	1	1	1
	[M − H]−	997.1	997.9	−0.9
10	[M + Na]+	1,334.5	1,337.2	−2.7	1	1	3	2	2	0
	[M − H]−	1,310.2	1,313.2	−3
11	[M + Na]+	1,034.7	1,036	−1.2	1	1	3	1	1	0
	[M − H]−	1,010.8	1,012	−1.1
12	[M + Na]+	1,612.8	1,817.8	205.0	1	2	3	2	2	0
	[M − H]−	1,589.2	1,793.8	204.6
13	[M + Na]+	1,896.5	1,817.8	78.7	2	2	3	2	2	0
	[M − H]−	1,872.5	1,793.8	78.7
14	[M + H]+	1,384.1	1,385.5	1.4	1	1	4	2	2	0
	[M − H]−	1,382.6	1,383.5	0.9
15	[M + Na]+	1,815.9	1,817.8	−1.9	2	2	3	2	2	0
	[M − H]−	1,792.3	1,793.8	−1.5
16	[M + H]+	1,872.6	1,795.8	76.8	2	2	3	2	2	0
	[M − H]−	1,871.3	1,793.8	77.5
17a	[M + H]+	1,872.6	1,795.8	76.8	2	2	3	2	2	0
	[M − H]−	1,871.5	1,793.8	77.3
17b	[M + H]+	1,590.7	1,795.8	205.1	1	2	3	2	2	0
	[M − H]−	1,588.0	1,793.8	205.8
18	[M + Na]+	1,773.4	1,817.8	−44.4	2	2	3	2	2	0
	[M − H]−	1,749.5	1,793.8	−44.3
19	[M + Na]+	1,773.4	1,817.8	−44.4	2	2	3	2	2	0
	[M − H]−	1,749.5	1,793.8	−44.3
20	[M + H]+	1,794.9	1,795.8	0.9	2	2	3	2	2	0
	[M − H]−	1,792.8	1,793.8	1.0
21	[M + Na]+	1,816.6	1,817.8	1.2	2	2	3	2	2	0
	[M − H]−	1,792.8	1,793.8	1.0
22	[M + H]+	1,753.0	1,795.8	−42.8	2	2	3	2	2	0
	[M − H]−	1,750.2	1,793.8	−43.6
23	[M + H]+	1,753.0	1,795.8	−42.8	2	2	3	2	2	0
	[M − H]−	1,750.2	1,793.8	−43.6
24	[M + Na]+	1,945.8	1,945.9	−0.1	2e	2e	4e	2e	2e	1e
	[M − H]−	1,920.5	1,921.9	−1.4
25	[M + Na]+	1,945.8	1,945.9	−0.1	2	2	4	2	2	1
	[M − H]−	1,921.5	1,921.9	−0.4
26	[M + Na]+	1,889.5	1,888.9	0.6	2	2	4	2	2	0
	[M − H]−	1,865.1	1,864.9	0.2
27	[M + Na]+	1,961.3	1,959.9	1.4	2	2	5	2	2	0
	[M − H]−	1,936.8	1,935.9	0.9
28	[M + Na]+	2,743.5	2,740.7	−2.8	3	3	5	3	3	0
	[M − H]−	2,718.3	2,716.7	−1.6
29	[M + Na]+	2,537.6	2,739.7	202.1	2	3	5	3	3	0
	[M − H]−	2,513.4	2,716.7	203.3
30	[M + H]+	2,719.9	2,718.7	1.2	3	3	5	3	3	0
	[M − H]−	2,717.6	2,716.7	0.9
31	[M + H]+	2,718.3	2,718.7	−0.4	3	3	5	3	3	0
	[M − H]−	2,716.1	2,716.7	−0.1
32	[M + Na]+	2,701.6	2,740.7	−40.7	3	3	5	3	3	0
	[M − H]−	2,674.7	2,716.7	−42.0
33	[M + Na]+	2,701.6	2,740.7	40.6	3	3	5	3	3	0
	[M − H]−	2,674.7	2,716.7	42.0
34	[M + Na]+	2,868.4	2,868.6	0.2	3	3	6	3	3	1
	[M − H]−	2,843.0	2,844.6	1.1
35	[M + H]+	3,642.8	3,641.6	1.2	4	4	7	4	4	0
	[M − H]−	3,638.5	3,639.6	1.1
36	[M + H]+	1,774.9	1,794.8	−19.9	2	2	3	2	2	0
	[M − H]−	1,772.7	1,793.8	−21.1
37	[M + Na]+	3,662.3	3,663.6	−1.3	4	4	7	4	4	0
	[M − H]−	3,635.5	3,639.6	−4.1
38	[M + H]+	2,700.1	2,718.7	−18.6	3	3	5	3	3	0
	[M − H]−	2,696.8	2,716.7	−19.9
A1	[M + Na]+	1,800.5	1,817.8	17.3	2	2	3	2	2	0
	[M − H]−	1,775.3	1,793.8	18.5
B1	[M + H]+	1,014.7	1,013.9	0.8	1	1	3	1	1	0
	[M − H]−	1,012.8	1,011.9	0.9
B2	[M + Na]+	993.7	1,035.9	−42.2	1	1	3	1	2	0
	[M − H]−	969.3	1,011.9	−42.6
B3	[M + H]+	1,255.5	1,257.2	−1.7	1	1	4	1	1	0
	[M − H]−	1,253.3	1,255.2	−1.9
B4	[Na + H]+	1,946.0	1,945.9	0.1	2	2	4	2	2	1
	[M − H]−	1,921.3	1,921.9	−0.6
B5	[M + H]+	2,016.3	1,937.9	78.4	2	2	5	2	2	0
	[M − H]−	2,013.7	1,935.9	77.8
B6	[M + H]+	1,937.1	1,937.9	0.8	2	2	5	2	2	0
	[M − H]−	1,934.4	1,935.9	1.5
B7	[M + Na]+	1,959.8	1,959.9	0.1	2	2	5	2	2	0
	[M − H]−	1,935.1	1,935.9	0.8
B8	[M + Na]+	1,916.3	1,959.9	−43.6	2	2	5	2	2	0
	[M − H]−	1,892.6	1,935.9	−43.3
B9	[M + Na]+	1,916.3	1,959.9	−43.6	2	2	5	2	2	0
	[M − H]−	1,892.6	1,935.9	−43.3
B10	[M + Na]+	1,875.3	1,959.9	−84.2	2	2	5	2	2	0
	[M − H]−	1,850.8	1,935.9	−84.2
B11	[M + Na]+	2,882.1	2,882.8	0.7	3	3	7	3	3	0
	[M − H]−	2,858.2	2,858.8	0.6
B12	[M + Na]+	2,881.5	2,882.8	1.3	3	3	7	3	3	0
	[M − H]−	2,857.1	2,858.8	1.7
B13	[M + Na]+	2,879.6	2,882.8	3.2	3	3	7	3	3	0
	[M − H]−	2,854.7	2,858.8	4.1
B14	[M + Na]+	2,837.8	2,882.8	45.0	3	3	7	3	3	0
	[M − H]−	2,813.3	2,858.8	45.5
B15	[M + Na]+	2,837.3	2,882.8	45.5	3	3	7	3	3	0
	[M − H]−	2,815.1	2,858.8	43.7
B16	[M + Na]+	3,804.0	3,805.7	1.7	4	4	9	4	4	0
	[M − H]−	3,780.4	3,781.7	1.3
B17	[Na + H]+	1,916.1	1,937.9	21.8	2	2	5	2	2	0
	[M − H]−	1,913.8	1,935.9	22.1

^aMuropeptides are numbered as indicated in Fig. 1. 

^bDifference between observed and calculated protonated, sodiated, or deprotonated molecular mass values. Boldface characters denote m/z values calculated as the most likely combinations of the list components which nevertheless deviated largely from the observed values. For explanation, see text. 

^cGlc, N-acetylglucosamine. 

^dMur, N-acetylmuramitol. 

^eNot determined but estimated from mass value.