Peptidoglükaani

Peptidoglükaani, also known as peptidoglycan, 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 polysaccharide chains of peptidoglycan are made up of alternating residues of N-acetylglucosamine and N-acetylmuramic acid. The peptide chains are short amino acid chains that are cross-linked to each other, providing strength and rigidity to the cell wall. The structure and composition of peptidoglycan vary between bacterial species, and this variation is often used in bacterial classification.

The peptidoglycan layer is essential for bacterial survival, as it provides structural support and protects the cell from osmotic lysis. The thickness and cross-linking of the peptidoglycan layer differ between Gram-positive and Gram-negative bacteria. Gram-positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thinner layer located in the periplasmic space between the inner and outer membranes.

The synthesis of peptidoglycan is a complex process that occurs in multiple stages, involving enzymes that are targeted by certain antibiotics, such as penicillin. These antibiotics inhibit the formation of peptide cross-links, weakening the cell wall and leading to bacterial cell death. This selective toxicity makes peptidoglycan synthesis a crucial target for antibacterial drug development.