ABSTRACT
Undecaprenyl pyrophosphate synthase (UppS) is an essential enzyme in bacterial cell wall synthesis. Here we report the discovery of Staphylococcus aureus UppS inhibitors from an Encoded Library Technology screen and demonstrate binding to the hydrophobic substrate site through cocrystallography studies. The use of bacterial strains with regulated uppS expression and inhibitor resistant mutant studies confirmed that the whole cell activity was the result of UppS inhibition, validating UppS as a druggable antibacterial target.
Subject(s)
Alkyl and Aryl Transferases/antagonists & inhibitors , Anti-Bacterial Agents/pharmacology , Drug Discovery , Enzyme Inhibitors/pharmacology , Pyrazoles/pharmacology , Staphylococcus aureus/drug effects , Alkyl and Aryl Transferases/metabolism , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Dose-Response Relationship, Drug , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Microbial Sensitivity Tests , Models, Molecular , Molecular Structure , Pyrazoles/chemical synthesis , Pyrazoles/chemistry , Staphylococcus aureus/enzymology , Structure-Activity RelationshipABSTRACT
As a potential target for obesity, human BCATm was screened against more than 14 billion DNA encoded compounds of distinct scaffolds followed by off-DNA synthesis and activity confirmation. As a consequence, several series of BCATm inhibitors were discovered. One representative compound (R)-3-((1-(5-bromothiophene-2-carbonyl)pyrrolidin-3-yl)oxy)-N-methyl-2'-(methylsulfonamido)-[1,1'-biphenyl]-4-carboxamide (15e) from a novel compound library synthesized via on-DNA Suzuki-Miyaura cross-coupling showed BCATm inhibitory activity with IC50 = 2.0 µM. A protein crystal structure of 15e revealed that it binds to BCATm within the catalytic site adjacent to the PLP cofactor. The identification of this novel inhibitor series plus the establishment of a BCATm protein structure provided a good starting point for future structure-based discovery of BCATm inhibitors.