Staphylococcus aureus, peptidoglycan

A -acetylmuramic acid) residues. These chains are cross-linked via peptide structures. Part of the peptidoglycan of Staphylococcus aureus is shown here. Amino acid abbreviations are given in Chapter 13. 

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).

Fig. 8. Basic structural unit of a peptidoglycan of the bacterial cell wall of Staphylococcus aureus...

It is often reserved as the drug of last resort . Vancomycin has increasingly become a first-line therapy in resistant Staphylococcus aureus infections. Vancomycin prevents NAM acid and NAG-peptide subunits from being incorporated into the peptidoglycan matrix the large hydrophilic molecule forms hydrogen-bond interactions with the terminal D-alanyl-D-alanine moieties of the NAM/NAG-peptides (Figure 20.8). 

In addition to the variations of the GT-A and GT-B fold described above for sialyltransferases (7, 8) and fucosyltrans-ferases (17), a distinct GT-C fold family has been predicted for GTs that use lipid linked donors. The crystal structures of the GT domain of the peptidoglycan glycosyltransferase from Staphylococcus aureus (18) (Fig. 3f) and Aquifex aeolicus, (26) show structural similarity to the bacteriophage k-lysozyme. These novel structures demonstrate the possibility of additional folds. 

Notably, 90% of AD patients show lesions colonized with Staphylococcus aureus and exhibit a significant reduction of colonization in nonlesional skin [17-19], Various products of S. aureus such as peptidoglycan and superantigens are known to induce the expression of proinflammatory cytokines in monocytes and dendritic cell subsets [20]. 

Figure 2 The PBP transpeptidation reaction, exemplified with the peptidoglycan of the Gram-positive bacterium Staphylococcus aureus.

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