Structure-Kinetic Relationship Studies for the Development of Long Residence Time LpxC Inhibitors.

UDP-3--(-3-hydroxymyristoyl)--acetylglucosamine deacetylase (LpxC) is a promising drug target in Gram-negative bacteria. Previously, we described a correlation between the residence time of inhibitors on LpxC (LpxC) and the post-antibiotic effect (PAE) caused by the inhibitors on the growth of . Given that drugs with prolonged activity following compound removal may have advantages in dosing regimens, we have explored the structure-kinetic relationship for LpxC inhibition by analogues of the pyridone methylsulfone () originally developed by Pfizer.

Impact of Target Turnover on the Translation of Drug-Target Residence Time to Time-Dependent Antibacterial Activity.

The translation of time-dependent drug-target occupancy to extended pharmacological activity at low drug concentration depends on factors such as target vulnerability and the rate of target turnover. Previously, we demonstrated that the postantibiotic effect (PAE) caused by inhibitors of bacterial drug targets could be used to assess target vulnerability, and that high levels of target vulnerability coupled with relatively low rates of target resynthesis resulted in a strong correlation between drug-target residence time and the PAE following compound washout. Although the residence time of inhibitors on UDP-3--acyl--acetylglucosamine deacetylase (LpxC) in (paLpxC) results in significant PAE, inhibitors of the equivalent enzyme in (ecLpxC) do not cause a PAE.

A Long Residence Time Enoyl-Reductase Inhibitor Explores an Extended Binding Region with Isoenzyme-Dependent Tautomer Adaptation and Differential Substrate-Binding Loop Closure.

The enoyl-acyl carrier protein (ACP) reductase (ENR) is a key enzyme within the bacterial fatty-acid synthesis pathway. It has been demonstrated that small-molecule inhibitors carrying the diphenylether (DPE) scaffold bear a great potential for the development of highly specific and effective drugs against this enzyme class. Interestingly, different substitution patterns of the DPE scaffold have been shown to lead to varying effects on the kinetic and thermodynamic behavior toward ENRs from different organisms.

Antibacterial Activity and Mode of Action of a Sulfonamide-Based Class of Oxaborole Leucyl-tRNA-Synthetase Inhibitors.

Benzoxaboroles are a class of boron-containing compounds with a broad range of biological activities. A subset of benzoxaboroles have antimicrobial activity due primarily to their ability to inhibit leucyl-tRNA synthetase (LeuRS) via the oxaborole tRNA-trapping mechanism, which involves the formation of a stable tRNA-benzoxaborole adduct in which the boron atom interacts with the 2'- and 3'-oxygen atoms of the terminal 3' tRNA adenosine. We sought to identify other antibacterial targets for this promising class of compounds by means of mode-of-action studies, and we selected a nitrophenyl sulfonamide based oxaborole () as a probe molecule because it had potent antibacterial activity (MIC of 0.