ABSTRACT
In this study, we identified antifolates with potent, targeted activity against whole-cell Mycobacterium tuberculosis (MTB). Liquid chromatography-mass spectrometry analysis of antifolate-treated cultures revealed metabolic disruption, including decreased pools of methionine and S-adenosylmethionine. Transcriptomic analysis highlighted altered regulation of genes involved in the biosynthesis and utilization of these two compounds. Supplementation with amino acids or S-adenosylmethionine was sufficient to rescue cultures from antifolate treatment. Instead of the "thymineless death" that characterizes folate pathway inhibition in a wide variety of organisms, these data suggest that MTB is vulnerable to a critical disruption of the reactions centered around S-adenosylmethionione, the activated methyl cycle.
Subject(s)
Antitubercular Agents/pharmacology , Folic Acid Antagonists/pharmacology , Folic Acid/metabolism , Methionine/analogs & derivatives , Methionine/metabolism , Mycobacterium tuberculosis/drug effects , Mycobacterium tuberculosis/metabolism , Dihydropteroate Synthase/antagonists & inhibitors , Drug Evaluation, Preclinical , Drug Synergism , Gene Expression Regulation, Bacterial/drug effects , Humans , Mycobacterium tuberculosis/enzymology , Mycobacterium tuberculosis/genetics , S-Adenosylmethionine/metabolism , Species Specificity , Tetrahydrofolate Dehydrogenase/metabolism , Triazines/pharmacologyABSTRACT
The glyoxylate shunt plays an important role in fatty acid metabolism and has been shown to be critical to survival of several pathogens involved in chronic infections. For Mycobacterium tuberculosis (Mtb), a strain with a defective glyoxylate shunt was previously shown to be unable to establish infection in a mouse model. We report the development of phenyl-diketo acid (PDKA) inhibitors of malate synthase (GlcB), one of two glyoxylate shunt enzymes, using structure-based methods. PDKA inhibitors were active against Mtb grown on acetate, and overexpression of GlcB ameliorated this inhibition. Crystal structures of complexes of GlcB with PDKA inhibitors guided optimization of potency. A selected PDKA compound demonstrated efficacy in a mouse model of tuberculosis. The discovery of these PDKA derivatives provides chemical validation of GlcB as an attractive target for tuberculosis therapeutics.
Subject(s)
Antitubercular Agents/chemistry , Antitubercular Agents/therapeutic use , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/therapeutic use , Malate Synthase/antagonists & inhibitors , Mycobacterium tuberculosis/enzymology , Tuberculosis/drug therapy , Animals , Antitubercular Agents/pharmacokinetics , Drug Design , Enzyme Inhibitors/pharmacokinetics , Female , Humans , Malate Synthase/metabolism , Mice , Mice, Inbred C57BL , Models, Molecular , Mycobacterium tuberculosis/drug effectsABSTRACT
[reaction: see text] An efficient allylic etherification of aliphatic alcohols with allylic carbonates has been achieved by an iridium catalysis using stoichiometric zinc alkoxides or a two-component bimetallic catalytic system where the Ir(I) catalyst acts on allylic carbonates to generate electrophiles while aliphatic alcohols are separately activated by Zn(II) coordination to function as nucleophilies. This reaction occurs with complete regiospecificity and tolerates a wide range of functional groups.
