The Polysaccharide Peptidoglycan and How it is Influenced by (Antibiotic) Stress
from: Bacterial Polysaccharides: Current Innovations and Future Trends (Edited by: Matthias Ullrich). Caister Academic Press, U.K. (2009)
The peptidoglycan or murein sacculus is the stress-bearing structure of bacterial cells. It consists of glycan strands cross-linked by peptide bridges. Even though studies on murein have a very long tradition, it is not known how the glycan strands are actually arranged. However, the chemical fine structure and the muropeptide composition of different Gram-negative and Gram-positive bacteria have been investigated in detail. This chapter discusses Escherichia coli and Staphylococcus aureus as representatives for both Gram forms. During cell growth the stress-bearing structure has to be elongated and/or divided by the insertion of new and elimination of old material without loosing its strength. Therefore multienzyme complexes containing both murein synthases and murein hydrolases have been postulated. Peptidoglycan biosynthesis is the target for many antibiotics such as β-lactams, D-cycloserine and glycopeptide-antibiotics like vancomycin. The last part of this chapter gives an overview of different bacterial strategies of bacteria for coping with antibiotic and osmotic stress read more ...