Peptidoglycane

The peptidoglycane (or muréine , or mucocomplexe , or mucopeptide ) is a Polymère of glycosaminopeptide where N-acétylglucosamine (NAG) and the acid N-acétylmuramique (NAM) are bound by osidic connections \ beta (1 \ rightarrow4) . The peptidoglycane form the bacterial Wall of the bacteria with positive Gram and negative Gram, ensuring the shape of the cells as well as a mechanical and physical protection. The thickness of the wall definitely higher in the bacteria is said to positive Gram and is in direct contact with the extracellular medium. Contrary in the bacteria with negative Gram, the peptidoglycane finer and is enchased between two plasmic membranes. It is this difference which confers a reactivity different from these two types of cells on the dye of Gram, in the beginning of dichotomic classification of the bacteria in " Gram positives" and " Gram négatives".

The Antibiotique Pénicilline prevents the synthesis of the peptidoglycane by the bacteria while being intercalated in polymer. This is why penicillin prevents the growth of the bacteria, but does not kill them.

  • N-acétylglucosamine is a Glucose related in 2C by a secondary amine to the grouping acetyl;

  • the N-acétylmuramique acid = NAG + Lactic acid bound by a osidic Connection to C3 of glucose;
  • the Peptide binding the NAM between them are bound by a peptide Liaison by the Lactic acid of the NAM.

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