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Peptidoglycan or murein is a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria, forming the cell wall. The sugar component consists of alternating residues of β-(1,4) linked N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). Attached to the N-acetylmuramic acid is a peptide chain of three to five amino acids. The peptide chain can be cross-linked to the peptide chain of another strand forming the 3D mesh-like layer. Peptidoglycan serves a structural role in the bacterial cell wall, giving structural strength, as well as counteracting the osmotic pressure of the cytoplasm. Peptidoglycan is also involved in binary fission during bacterial cell reproduction.
The cell envelope comprises the inner cell membrane and the cell wall of a bacterium. In gram-negative bacteria an outer membrane is also included. This envelope is not present in the Mollicutes where the cell wall is absent.
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References
- ↑ Seltmann, Guntram; Holst, Otto (2002). The Bacterial Cell Wall. Berlin: Springer. pp. 81–82. ISBN 3-540-42608-6.
- ↑ Dramsi S, Magnet S, Davison S, Arthur M (2008). "Covalent attachment of proteins to peptidoglycan". FEMS Microbiology Reviews. 32 (2): 307–20. doi: 10.1111/j.1574-6976.2008.00102.x . PMID 18266854.
- 1 2 3 Konovalova A, Silhavy TJ (2015). "Outer membrane lipoprotein biogenesis: Lol is not the end". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 370 (1679). doi:10.1098/rstb.2015.0030. PMC 4632606 . PMID 26370942.
- 1 2 Kovacs-Simon A, Titball RW, Michell SL (2011). "Lipoproteins of bacterial pathogens". Infection and Immunity. 79 (2): 548–61. doi:10.1128/IAI.00682-10. PMC 3028857 . PMID 20974828.
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- ↑ Vollmer, Waldemar (2007). "Structure and biosynthesis of the murein (peptidoglycan) sacculus". In Ehrmann, Michael (ed.). The Periplasm ([Online-Ausg.]. ed.). Washington, DC: ASM Press. pp. 198–213. ISBN 9781555813987.
- ↑ Butler T (2009). "Plague into the 21st century". Clinical Infectious Diseases. 49 (5): 736–42. doi: 10.1086/604718 . PMID 19606935.
- ↑ Smiley ST (2008). "Immune defense against pneumonic plague". Immunological Reviews. 225: 256–71. doi:10.1111/j.1600-065X.2008.00674.x. PMC 2804960 . PMID 18837787.
- ↑ McIntyre TM, Prescott SM, Weyrich AS, Zimmerman GA (2003). "Cell-cell interactions: leukocyte-endothelial interactions". Current Opinion in Hematology. 10 (2): 150–8. doi:10.1097/00062752-200303000-00009. PMID 12579042.