Diferenzas entre revisións de «Peptidoglicano»

 
== Estrutura ==
[[Ficheiro:Peptidoglycan en.svg|thumb|Peptidoglicano.]]
The peptidoglycan layer in the bacterial cell wall is a [[crystal lattice]] structure formed from linear chains of two alternating amino [[sugar]]s, namely [[N-Acetylglucosamine|''N''-acetylglucosamine]] (GlcNAc or NAG) and [[N-Acetylmuramic acid|''N''-acetylmuramic acid]] (MurNAc or NAM). The alternating sugars are connected by a β-(1,4)-[[glycosidic bond]]. Each MurNAc is attached to a short (4- to 5-residue) [[amino acid]] chain, containing [[alanine|<small>L</small>-alanine]], [[glutamic acid|<small>D</small>-glutamic acid]], [[meso-diaminopimelic acid|''meso''-diaminopimelic acid]], and [[alanine|<small>D</small>-alanine]] in the case of ''[[Escherichia coli]]'' (a Gram-negative bacteria) or [[alanine|<small>L</small>-alanine]], [[glutamine|<small>D</small>-glutamine]], [[lysine|<small>L</small>-lysine]], and <small>D</small>-alanine with a 5-glycine interbridge between tetrapeptides in the case of ''[[Staphylococcus aureus]]'' (a Gram-positive bacteria). These amino acids, except the <small>L</small>-amino acids, do not occur in proteins and are thought to help protect against attacks by most peptidases{{Citation needed|date=November 2008}}.
 
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