Investigation of new potent KDO-8-phosphate synthetase inhibitors

Antibiotics and bacterial resistance in the 21st century

Dangerous, antibiotic resistant bacteria have been observed with increasing frequency over the past several decades. In this review the factors that have been linked to this phenomenon are addressed. Profiles of bacterial species that are deemed to be particularly concerning at the present time are illustrated. Factors including economic impact, intrinsic and acquired drug resistance, morbidity and mortality rates, and means of infection are taken into account. Synchronously with the waxing of bacterial resistance there has been waning antibiotic development. The approaches that scientists are employing in the pursuit of new antibacterial agents are briefly described. The standings of established antibiotic classes as well as potentially emerging classes are assessed with an emphasis on molecules that have been clinically approved or are in advanced stages of development. Historical perspectives, mechanisms of action and resistance, spectrum of activity, and preeminent members of each class are discussed.

A simple synthesis of 2-keto-3-deoxy-D-erythro-hexonic acid isopropyl ester, a key sugar for the bacterial population living under metallic stress

2-Keto-3-deoxy-D-erythro-hexonic acid (KDG) is the key intermediate metabolite of the Entner Doudoroff (ED) pathway. A simple, efficient and stereoselective synthesis of KDG isopropyl ester is described in five steps from 2,3-O-isopropylidene-D-threitol with an overall yield of 47%. KDG isopropyl ester is studied as an attractive marker of a functional Entner Doudoroff pathway. KDG isopropyl ester is used to promote growth of ammonium producing bacterial strains, showing interesting features in the remediation of heavy-metal polluted soils.

Synthesis and antibacterial activity of mechanism-based inhibitors of KDO8P synthase and DAH7P synthase

KDO8PS (3-deoxy-D-manno-2-octulosonate-8-phosphate synthase) and DAH7PS (3-deoxy-D-arabino-2-heptulosonate-7-phosphate synthase) are attractive targets for the development of new anti-infectious agents. Both enzymes appear to proceed via a common mechanism involving the reaction of phosphoenolpyruvate (PEP) with arabinose 5-phosphate or erythrose-4-phosphate, to produce the corresponding ulosonic acids, KDO8P and DAH7P, respectively. The synthesis of new inhibitors closely related to the supposed tetrahedral intermediate substrates for the enzymes is described. The examination of the antibacterial activity of these derivatives is reported.

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.