Table 1.

Analysis of murein purified from H. pyloricells at different stages of the spiral-coccoid morphological transition

Embedded Image
  • a Relative molecular mass values for NaBH4-reduced muropeptides purified from spiral- and coccoid-cell murein. Measurements of the relative molecular mass for the sodiated molecular ions [M+Na]+ (not shown) confirmed the results presented in the table. Spiral cells were taken from a 5-h-old culture; coccoid cells were taken from a 15-day-old culture.

  • b Calculated as described by Glauner et al. (20).

  • c More than 95% of the cells had the indicated morphology.

  • d Numbers correspond with peaks in Fig. 1. In the lower part of the table, muropeptides are grouped according to structural similarity. Monomers, monomeric muropeptides (1 to 5 and 10); dimers, cross-linked muropeptides (6 to 9 plus 11 to 15); anhydro, muropeptides with (1→6)anhydro-muramic acid (10 to 15); dipeptide, muropeptides with dipeptide side chain (4);d-Ala–d–Ala, muropeptides with a pentapeptidic side chain terminated ind-Ala–d-Ala (5, 9, 10, and 15);d-Ala–Gly, muropeptides with a pentapeptidic side chain terminated in d-Ala–Gly (3 and 7).

  • e Muropeptides best fitting the relative molecular masses measured by MALDI-MS. Abbreviations: NAG, N -acetylglucosamine; NAM, N -acetylmuramic acid; (an)NAM, (1→6)anhydro- N -acetylmuramic acid.

  • f Culture in the exponential phase of growth.

  • g Culture in the early (4 h) stationary phase of growth.

  • h Muropeptides 11 and 12 and muropeptides 13 and 14 are position isomers for the (1→6)anhydro- N -acetylmuramic acid residue relative to the peptide bridge. The alternative positions for (an)NAM and NAM residues are shown in brackets.

  • i Presumably an unresolved mixture of two position isomers as for muropeptides 11 and 12 and muropeptides 13 and 14. The alternative positions for (an)NAM and NAM residues are shown in brackets.