Structure of the peptide network of pneumococcal peptidoglycan.

摘要: The peptide network of Streptococcus pneumoniae cell walls was solubilized using the pneumococcal autolytic amidase (N-acetylmuramoyl-L-alanine amidase, EC 3.5.1.28). material fractionated into size classes by gel filtration followed reverse-phase high-performance liquid chromatography which resolved population over 40 fractions. About 40% lysines present participate in cross-links between stem peptides. main components (3 monomers, 5 dimers, and 2 trimers), accounting for 77% all wall peptides, were purified. Their structures determined a combination amino acid end-group analysis, mass spectrometry, gas-phase sequencing. Two different types peptides found. In most abundant type there is an alanylserine cross-bridge alanine position 4 donor lysine at 3 acceptor peptide, as A3 peptidoglycan. second cross-link no intervening cross-bridge, A1 peptidoglycan Gram-negative bacteria. data indicate that has structural complexity comparable to recently shown some species.