Peptidoglycan

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Structure of peptidoglycan.

Peptidoglycan (PG, murein) is the basic polymer of the bacterial wall.

It makes up 30 % of the G+ wall and 10 % of the G− bacteria (archea and mycoplasmas do no have it). Otherwise, it does not occur anywhere in nature.

Composition of peptidoglycan[edit | edit source]

Polymeric glycan chains of glucosamine and muramic acid (ie. glucosamine linked by ether bond to lactic acid) – diagnostic significance (only in bacteria). Glycan chains are linked by oligopeptide chains (they form a rigid network surounding the entire bacterium, thus maintaining its shape).

There are a number of variations (more than 100 structural types):

  • Type A;
  • Type B.

Ther presence of D-amino acids is a characteristic marker. Bound teichoic acids, polar and non-polar lipids.

Isolated PG shows biological activities:

  • pyrogenicity;
  • antigenicity;
  • complement activation.

Clinic[edit | edit source]

Inhibition of PG biosynthesis by β-lactam antibiotics, which bind to enzymes synthesizing PG interpeptide bridges, is important, causing bacterial cell lysis. Lysozyme acts as a bacteriolytic enzzyme (regulates bacterial colonizatio), cleaving the β-1,4 glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine.


Links[edit | edit source]

Source[edit | edit source]

related articles[edit | edit source]

Source[edit | edit source]

  • JULÁK, Jaroslav. Introduction to medical bacteriology. 1st edition. Prague: Karolinum, 2006.  ISBN 80-246-1270-4

Kategorie:Mikrobiologie