UDP-MurNAc-pentapeptide

The second stage of this cascade takes place at the cytoplasmic surface of the bacterial cell membrane. In the first reaction, MraY catalyzes a pyrophosphate exchange reaction wherein the UDP-MurNAc-pentapeptide precursor is coupled to a membrane-anchored C55 lipid carrier with ejection of UMP to provide undecaprenylpyrophosphoryl-MurNAc-pentapeptide 4, also know as lipid I. In the second reaction, the MurG enzyme catalyzes the transfer of GlcNAc from a UDP-GlcNAc precursor to the C(4)-hydroxyl group of the lipid-linked MurNAc-pentapeptide. The product of this enzymatic reaction, lipid II5, is the... 

The wild-type UDP-MurNAc-L-Ala-y-D-Glu-L-Lys-D-Ala-D-Ala (UDP-MurNAc-pentapeptide) was first isolated from S. aureus in 1952 by James Park [77], Nicolas Gisch et al. reported the synthesis of the biotinylated Lys-type and DAP-type muramyl tripeptides through their UDP derivatives [78], Both compounds activated Nod2 in a cell-based assay, although the required minimal motif for the activation of Nod2 is muramyl dipeptide [79], The chemical synthesis of the UDP-MurNAc-pentapeptide 7 (Scheme 14.1) [19] was followed by the chemoenzymatic synthesis by Chi-Huey Wong [80] and Michio Kurosu [81], Wong et al. also synthesized the vancomycin-resistant UDP-MurNAc-L-Ala-y-D-Glu-L-Lys-D-Ala-D-Lac... 

UDP-A-MurNAc-depsipentapeptide) derivatives including fluorescent-labeled derivatives. Shin-ichiro Nishimura et al. reported the synthesis of UDP-MurNAc-pentapeptide derivatives possessing a levulinyl (Lev) group on the side chain of the Lys residue [82, 83] for subsequent introduction of fluorescent label or oligosaccharide moieties by oxime formation after their incorporation through cell-wall biosynthesis. The 4-fluorinated UDP-MurNAc-pentapeptide was also synthesized as a stable biosynthesis inhibitor [84],... 

Briefly, in E. colithe biosynthesis of PG initiates in cytosol with the formation of UDP-Macetylmuramic acid (UDP-MurNAc) from UDP-GlcNAc by a two-step reaction catalyzed by MurA and MurB. UDP-MurNAc is subsequently transformed into UOP-MurNAc-L-Ala-D-Glu-wcro-DAP-D-Ala-D-Ala (UDP-MurNAc-pentapeptide (UDP-MurNAc-PP) or Park s nucleotide) by sequential addition of L-Ala, d-G1u, wcro-DAP, and D-Ala-D-Ala catalyzed by MurC, D, E, and F, respectively. 

FlO. 4, The nucleotide precursors UDP-GlNAc and UDP-MurNAc-pentapeptide in Staphylococcus aureus. Note that D-glutamic acid is linked to the a-amino group of L-lysine through its y-carboxyl group and that the a-carboxyl group of E)-glutaniic acid is free. The same precursors are found in Escherichia coli except that meso-diaminopimelic acid replaces L-lysine. 

The anhydroMurNAc is removed, and new UDP-MurNAc and D-Ala-D-Ala units are added salvaging the tripeptide unit. The repaired UDP-MurNA-pentapeptide can then reenter the biosynthetic pathway (Fig. 20-9). 

Formation of UDP-N-acetylmuramic acid pentapeptide stage 1 of peptidoglycan biosynthesis. The steps in this pathway are discussed in the text. MurNAc = N-acetylmuramic acid, PEP = phosphoenolpyruvate. 

Scheme 2, Biosynthesis of UDP-IV-acetylmuramyl-pentapeptide. (MurNAc = IV-acetylmuramic acid, PEP = enolpyruvate phosphate.)...

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