The Morphological Transition of Helicobacter pyloriCells from Spiral to Coccoid Is Preceded by a Substantial Modification of the Cell Wall

摘要

The peptidoglycan (murein) of Helicobacter pylori has been investigated by high-performance liquid chromatography and mass spectrometric techniques. Murein from H. pyloricorresponded to the A1γ chemotype, but the muropeptide elution patterns were substantially different from the one forEscherichia coli in that the former produced high proportions of muropeptides with a pentapeptide side chain (about 60 mol%), with Gly residues as the C-terminal amino acid (5 to 10 mol%), and with (1→6)anhydro-N-acetylmuramic acid (13 to 18 mol%). H. pylori murein also lacks murein-bound lipoprotein, trimeric muropeptides, and (l-d) cross-linked muropeptides. Cessation of growth and transition to coccoid shape triggered an increase inN-acetylglucosaminyl-N-acetylmuramyl–l-Ala–d-Glu (approximately 20 mol%), apparently at the expense of monomeric muropeptides with tri- and tetrapeptide side chains. Muropeptides with (1→6)anhydro-muramic acid and with Gly were also more abundant in resting cells.