Peptidoglycans bacterial

Many different types of carbohydrate-containing molecules are located on the surface of microbial cells. Some of these are components of die microbial cell wall and are limited to certain types of micro-organisms such as bacterial peptidoglycan, lipopolysaccharides, techoic adds and yeast mannans. Other polysaccharides are not... 

Fig. 8.3 A, comparison of the stmcture of the nucleus of the penicillin molecule with B, the D-alanyl-D-alanine end group of the precursor of bacterial peptidoglycan. The broken lines show the correspondence in position between the labile bond of penicillin and the bond broken during the transpeptidation reaction associated with the crosslinking in peptidoglycan. 

A. Fox and R. M. T. Rosario, Quantification of muramic acid, a marker for bacterial peptidoglycan in dust collected from hospital and home air-conditioning filters using gas-chromatography mass spectrometry. Indoor Air-Intemat. J. Air Quality Cl. 4 239 (1994). 

The structure of the native immunostimulatory MDPs was found to be IV-acetyl muramyl-L-alanyl-D-isoglutamine. (/V-Acetyl muramic acid is a base component of bacterial peptidoglycan.) Native TDM is a potent pyrogen and is too toxic for general use as an adjuvant. The molecular basis underlining MDP s adjuvanticity remains to be fully elucidated. Administration of MDP, however, is known to activate a number of cell types that play direct/indirect roles in immune function, and induces the secretion of various immunomodulatory cytokines (Table 13.14). 

Bacterial peptidoglycans o-amino acids and the antibacterial action of penicillins... 

Synthesis of Cell Wall Polysaccharides Plant Cellulose and Bacterial Peptidoglycan 775... 

T Although D-amino acids do not generally occur in proteins, they do serve some special functions in the structure of bacterial cell walls and peptide antibiotics. Bacterial peptidoglycans (see Fig. 20-23) contain both D-alanine and D-glutamate. D-Amino acids arise directly from the l isomers by the action of amino acid racemases, which have pyridoxal phosphate as cofactor (see Fig. 18-6). Amino acid racemization is uniquely important to bacterial metabolism, and enzymes such as... 

Adds a major new section on the synthesis of cellulose and bacterial peptidoglycan... 

Figure 8-29 (A) Repeating unit of structure of a bacterial peptidoglycan (murein). Some connecting bridges are pentaglycine (Staphylococcus aureus), trialanylthreonine (Micrococcus roseum), and polyserine (S. epidermis).

Figure 20-9 Biosynthesis of bacterial peptidoglycans. See Fig. 8-29 for details of the peptidoglycan structures. Green arrows show alternative route used by gram-positive bacteria.

Formation of the three-dimensional network of bacterial peptidoglycan includes synthesis both of glycosidic and peptide linkages, but only the former type of reaction is discussed in this Section. The assembly of the carbohydrate chains of a peptidoglycan has been shown to occur through a block mechanism. The initial reaction consists in transfer of N-acetyl-muramyl-pentapeptide phosphate from the corresponding UDP derivative... 

Bugg TDH (1999) Bacterial peptidoglycan biosynthesis and its inhibition. Comprehensive Natural Products Chemistry, Vol 3. Elsevier, Amsterdam, pp 241-294. 

T Skarzynski, A Mistry, A Wonacott, SE Hutchinson, VA Kelly, K Duncan. Structure of UDP-N-acetylglucosamine enolpyruvyl transferase, an enzyme essential for the synthesis of bacterial peptidoglycan, complexed with substrate UDP-N-acetylglucosamine and the drug fosfomycin. Structure 4 1465-1474, 1996. 

J van Heijenoort. Assembly of the monomer unit of bacterial peptidoglycan. Cell Mol Life Sci 54 300-304, 1998. 

Humljan, J., Kotnik, M., Boniface, A., et al. (2006) A new approach towards peptidosulfonamides synthesis of potential inhibitors of bacterial peptidoglycan biosynthesis enzymedMurD andMurE. Tetrahedron 62,10980-10899. 

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