D-alanine—D-alanine ligase

In enzymology, a D-alanine—D-alanine ligase (EC 6.3.2.4) is an enzyme that catalyzes the chemical reaction

ATP 2 D-alanine ${\displaystyle \rightleftharpoons }$ ADP phosphate D-alanyl-D-alanine

Thus, the two substrates of this enzyme are ATP and D-alanine, whereas its 3 products are ADP, phosphate, and D-alanyl-D-alanine.

This enzyme belongs to the family of ATP-grasp ligases, specifically those forming carbon-nitrogen bonds as acid-D-amino-acid ligases (peptide synthases). The systematic name of this enzyme class is D-alanine:D-alanine ligase (ADP-forming). Other names in common use include alanine:alanine ligase (ADP-forming), and alanylalanine synthetase. This enzyme participates in d-alanine metabolism and peptidoglycan biosynthesis. Phosphinate and D-cycloserine are known to inhibit this enzyme.

The N-terminal region of the D-alanine—D-alanine ligase is thought to be involved in substrate binding, while the C-terminus is thought to be a catalytic domain.

Structural studies

As of late 2007, 8 structures have been solved for this class of enzymes, with PDB accession codes 1EHI, 1IOV, 1IOW, 2DLN, 2FB9, 2I80, 2I87, and 2I8C.

References

Further reading

• Ito, E; Strominger JL (1962). "Enzymatic synthesis of the peptide in bacterial uridine nucleotides II. Enzymatic synthesis and addition of D-alanyl-D-alanine". J. Biol. Chem. 237: 2696–2703. doi:10.1016/S0021-9258(19)73809-5.
• Neuhaus FC (1962). "Kinetic studies on D-Ala-D-Ala synthetase". Fed. Proc. 21: 229.
• van Heijenoort J (2001). "Recent advances in the formation of the bacterial peptidoglycan monomer unit". Nat. Prod. Rep. 18 (5): 503–19. doi:10.1039/a804532a. PMID 11699883.