Inhibition of the Antibacterial Target UDP-(3-O-acyl)-N-acetylglucosamine Deacetylase (LpxC): Isoxazoline Zinc Amidase Inhibitors Bearing Diverse Metal Binding Groups

UDP-3-O-[R-3-hydroxymyristoyl]-GlcNAc deacetylase (LpxC) is a zinc amidase that catalyzes the second step of lipid A biosynthesis in Gram negative bacteria. Known inhibitors of this enzyme are oxazolines incorporating a hydroxamic acid at the 4-position, which is believed to coordinate to the single essential zinc ion. A new structural class of inhibitors was designed to incorporate a more stable and more synthetically versatile isoxazoline core. The synthetic versatility of the isoxazoline allowed for a broad study of metal binding groups. Nine of 17 isoxazolines, each incorporating a different potential metal binding functional group, were found to exhibit enzyme inhibitory activity, including one that is more active than the corresponding hydroxamic acid. Additionally, a designed affinity label inhibits LpxC in a time-dependent manner.