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Search The CSA
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Catalytic Site Atlas

CSA LITERATURE entry for 1uag

E.C. nameUDP-N-acetylmuramoyl-L-alanine---D-glutamate ligase
SpeciesEscherichia coli (Bacteria)
E.C. Number (IntEnz) 6.3.2.9
CSA Homologues of 1uagThere are 16 Homologs
CSA Entries With UniProtID P14900
CSA Entries With EC Number 6.3.2.9
PDBe Entry 1uag
PDBSum Entry 1uag
MACiE Entry M0317

Literature Report

IntroductionUDP-N-acetylmuramoylalanine-D-glutamate ligase catalyses the formation of the peptide bond between UDP-N-acetylmuramoyl-L-alanine and D-glutamate in peptidoglycan biosynthesis. Peptidoglycan is formed as linear repeating disaccharide chains interconnected by a short peptide moiety. It is found in bacterial cell walls and hence peptidoglycan biosynthetic enzymes are possible targets for antibacterial drugs.
MechansimThe reaction can be broken down into three steps. The first is the initial phosphorylation of the UMA carboxylate to form the acyl-phosphate. The intermediate would be stabilised by Lys115 and the two divalent cations in the active site. The second is the nucleophilic attack by the amine of D-glutamate producing a tetrahedral intermediate. The formation of the tetrahedral adduct requires a catalytic base to abstract the proton from the D-glutamate amine. This is achieved by either D-glutamate binding in the from solution in the free base form or the deprotonation is assisted by the gamma phosphate of ATP. In the last step the tetrahedral intermediate collapses to yield UDP-N-acetylmuramoyl-L-alanyl-D-glutamate, ADP and inorganic phosphate. This requires another catalytic base to remove the second proton. His183 is thought to act as such a base.
Reaction

Catalytic Sites for 1uag

Annotated By Reference To The Literature - Site 2 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
AsnA138139macie:sideChain
HisA183184macie:sideChain
LysA115116macie:sideChain

Literature References

Notes:
Bertrand JA
Determination of the MurD mechanism through crystallographic analysis of enzyme complexes.
J Mol Biol 1999 289 579-590
PubMed: 10356330
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