TABLE 2.

Relative distribution (%) of muropeptides in C. difficile 630 grown in BHI, in BHI plus ampicillin, and from ldt_cd1, ldt_cd2, and ldt_cd1ldt_cd2 mutant strains

Percentages were calculated from the values shown in Table I.

Muropeptide	Strains
	630	630 + Ampicillin	ldtcd1 mutant	ldtcd2 mutant	ldtcd1ldtcd2 mutant
Monomers	35.1	33.6	49.8	46.9	51.5
Dimers	56.6	56	29.9	36.6	34.3
3-3 Cross-linka	41.3	48.6	19	25.7	22.7
4-3 Cross-link	15.3	7.4	10.9	10.9	11.6
No cross-link (peaks X and Y)	0	0	11.4	7.7	7.2
Trimers	8.3	10.4	8.9	6	5.4
One cross-link (peakZ)	0	0	1.8	2.7	1.6
Cross-linking indexb	33.8	34.9	18.2	21.5	19.8

^a Percentages were calculated using muropeptides dimers with determinated 3-3 cross-link.

^b The cross-linking index was calculated with the formula (1/2Σdimers + 2/3Σtrimers)/Σ all muropeptides (44). Dimers without cross-link were accounted as two monomers. In the same way, trimers with only one cross-link were accounted as one dimer and one monomer.