Phosphinate Inhibitors of the D-Glutamic Acid-Adding Enzyme of Peptidoglycan Biosynthesis.
We report the synthesis and initial evaluation of the first effective inhibitors of the D-glutamic acid-adding enzyme (UDP-N-acetylmuramoyl-L-alanine:D-glutamate ligase or MurD). This enzyme plays a key role in bacterial peptidoglycan biosynthesis and is therefore a target for antibiotic design. Phosphinic acid 3 is a dipeptide analog linked to uridine diphosphate by a hydrophobic spacer. It is a good inhibitor of the enzyme (IC(50) = 0.68 &mgr;M) as it closely resembles the tetrahedral intermediate that is presumed to form in the ligation reaction. Compound 4 lacks the terminal UMP group, and compound 5 lacks both the linker and UDP functionalities. These are less effective inhibitors of the enzyme with IC(50) values of 29 &mgr;M and >1 mM, respectively. Preincubation of the enzyme in the presence of inhibitor 3 and ATP does not result in irreversible inhibition or in the formation of a slowly decomplexing species, suggesting that the phosphinic acid is not phosphorylated in the active site.
Tanner
Martin E.
ME
Department of Chemistry, University of British Columbia, Vancouver, British Columbia, V6T 1Z1, Canada and URA 1131 du CNRS, Université de Paris-Sud, 91405 Orsay, France.
Vaganay
Sabine
S
van Heijenoort
Jean
J
Blanot
Didier
D