D-alanine—alanyl-poly(glycerolphosphate) ligase

D-alanine—alanyl-poly(glycerolphosphate) ligase (also known as D-Ala-PGP ligase) is an enzyme that catalyzes the addition of D-alanine to poly(glycerolphosphate) (PGP) teichoic acid. Specifically, it catalyzes the following reaction:

D-alanine + PGP + ATP <=> D-alanyl-PGP + ADP + phosphate

This enzyme is vital in the biosynthesis of cell walls in Gram-positive bacteria. Teichoic acids are anionic glycopolymers found within the cell wall of these bacteria and play crucial roles in maintaining cell shape, regulating cell division, and mediating interactions with the environment. D-alanyl modification of PGP is a common modification that contributes to the overall negative charge of the cell wall, influencing its interactions with cationic antimicrobial peptides and bacteriophages.

The activity of D-Ala-PGP ligase is essential for bacterial survival and virulence. Disrupting the enzyme's function can compromise the integrity of the cell wall, rendering the bacteria more susceptible to environmental stresses and host defenses. As such, D-Ala-PGP ligase has emerged as a potential target for the development of novel antibacterial agents.

The enzyme typically requires ATP as an energy source to drive the ligation reaction. The D-alanine is transferred to the PGP backbone, forming a D-alanyl-PGP derivative. The precise mechanism of action and the structure of the enzyme may vary depending on the bacterial species. Research on D-Ala-PGP ligases aims to understand their structure-function relationship and identify inhibitors that can selectively target these enzymes in pathogenic bacteria.