Meso-Diaminopimelic acid

The peptidoglycan structure of bacterial cell walls. The shaded areas represent points of attachment of this macromolecule to the rest of the cell wall. The amino sugar units are joined end to end to form long, straight chains. The peptides form cross-links when the amino group of a meso-diaminopimelic acid in one chain replaces the terminal alanine in another chain. Source ... 

In Gram-negative bacteria, as well as some Gram-positive strains, meso-diaminopimelic acid (meso-DAP) is incorporated in place of L-Lys. 

Figure 3 Schematic representation of the cytoplasmic steps of biosynthesis of UDP-N-acetylmuramic acid pentapeptide in E. coli. UDP-NAcGlc, UDP-N-acetylglucosamine PEP, phosphoenolpyruvate UDP-NAcEPGlc, UDP-N-acetylenolpyruvylglucosamine UDP-NAcMur, UDP-N-acetylmuramic acid meso-DAV, meso-diaminopimelic acid.

LpxC UDP-3-0-(R-3-hydroxymyristoyl)-/ /-acetylglucosamine deacetyiase mDAP meso-diaminopimelic acid... 

L-Lysine is produced in some organisms by decarboxylation of meso-diaminopimelic acid. This enzyme has a pH optimum over 7, in contrast with the acidic pH optima of the other bacterial amino acid decarboxylases. It is extremely specific it does not attack higher or lower homologs, or compounds in which the methylene carbons bear a methyl or hydroxyl group. This has also been shown to be a PALPO-requiring enzyme. 

D-glutamic acid meso-diaminopimelic acid D-alanine... 

The occurrence of iV -succinyl-a-amino- -ketopimelio acid and its transamination to succinyl-L-diaminopimelic acid has also been reported 196). The transaminase has been purified about 150-fold chiefly by means of chromatography on DEAE-cellulose. This transaminase was shown to be distinct from several other transaminases present in E. coli. The purified enzyme was specific for glutamate as an amino group donor in the formation of succinyldiaminopimelic acid. Succinyl-meso-diaminopimelic acid was inactive as a substrate. 

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