In vitro testing of putative Escherichia coli MurA inhibitors (582.1)

Abstract

Antibiotic resistance necessitates the continuous development of novel inhibitors targeting a variety of bacterial pathways. The pathway for the synthesis of peptidoglycan, a necessary component of the bacterial cell wall, is an ideal target for antibiotic development for two reasons: 1) the cell wall is a prokaryote‐specific structure, and 2) the cell wall is necessary for bacterial survival. MurA, the target of current study, is the enzyme that catalyzes the first step in peptidoglycan biosynthesis. Our objective is to develop novel inhibitors that competitively bind to the MurA catalytic sight for UDP‐N‐acetylglucosamine. In an effort to study the effects of various putative inhibitors on MurA, the active enzyme was purified in high concentrations. In vitro tests of the known inhibitor fosfomycin and other potential inhibitors were conducted using the purified enzyme. The Malachite green assay as previously described was used to determine the IC50 values for a number of potential inhibitors. Of the compounds assayed, two salts, VS5 and BCB33b, exhibited consistent IC50 values of 160 uM and 300 uM respectively. The IC50 values of the two putative inhibitors are the lowest we have seen out of all the tested compounds; therefore, VS5 and BCB33b will be tested further in vitro, in vivo, and in silico in their salt and acid forms for comparison against the known inhibitor fosfomycin.Grant Funding Source: Faculty Development Committee, Centre College