Inhibition of Methionyl-tRNA Synthetase by REP8839 and Effects of Resistance Mutations on Enzyme Activity

Green, Louis S.; Bullard, James M.; Ribble, Wendy; Dean, Frank B.; Ayers, David F.; Ochsner, Urs A.; Janjić, Nebojša; Jarvis, Thale C.

doi:10.1128/aac.00275-08

Cited by 43 publications

(49 citation statements)

References 45 publications

(51 reference statements)

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“…Fewer differences in the inhibitor binding site were observed between trypanosomatid and human mitochondrial MetRS enzymes, with only 5 of 25 residues being different. This also fits with published data that REP8839 inhibits the human mitochondrial enzyme with a K i of 10 nM (12). Of note, REP8839 inhibits the S. aureus MetRS with a K i of 10 pM (12), suggesting that extremely tight binding is possible.…”

Section: Discussionsupporting

confidence: 90%

“…This fits with published data that the diaryl diamine REP8839 (Fig. 6) is essentially inactive on the human cytosolic enzyme, with K i on May 11, 2018 by guest http://aac.asm.org/ being Ͼ20,000 nM (12). Fewer differences in the inhibitor binding site were observed between trypanosomatid and human mitochondrial MetRS enzymes, with only 5 of 25 residues being different.…”

Section: Discussionsupporting

confidence: 90%

“…The concentrations of the compounds are represented as factors of their EC 50 s determined in a 48-h incubation. At defined times (6,12,24,36, 48 h), the cells were removed, centrifuged, washed, and resuspended in medium without the compounds. The cultures were allowed to grow until the 48-h time point from the first exposure to the compounds, at which time the viability of the cultures was assessed using AlamarBlue as described above.…”

Section: Methodsmentioning

confidence: 99%

“…The methionyl-RS (MetRS) of T. brucei has particularly attracted our interest because of significant differences with the mammalian orthologs (discussed herein) and because of the existence of compounds under development in Pharma targeting the homologous enzyme in bacteria. MetRS enzymes in general are divided into two major forms on the basis of sequence similarity and sensitivity to inhibitors (3,12). MetRS1 is the form commonly found in Gram-positive bacteria, including Staphylococcus aureus and Streptococcus pyogenes.…”

mentioning

confidence: 99%

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Selective Inhibitors of Methionyl-tRNA Synthetase Have Potent Activity against Trypanosoma brucei Infection in Mice

Shibata

Gillespie

Kelley

et al. 2011

Antimicrob Agents Chemother

125

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Human African trypanosomiasis continues to be an important public health threat in extensive regions of sub-Saharan Africa. Treatment options for infected patients are unsatisfactory due to toxicity, difficult administration regimes, and poor efficacy of available drugs. The aminoacyl-tRNA synthetases were selected as attractive drug targets due to their essential roles in protein synthesis and cell survival. Comparative sequence analysis disclosed differences between the trypanosome and mammalian methionyl-tRNA synthetases (MetRSs) that suggested opportunities for selective inhibition using drug-like molecules. Experiments using RNA interference on the single MetRS of Trypanosoma brucei demonstrated that this gene product was essential for normal cell growth. Small molecules (diaryl diamines) similar to those shown to have potent activity on prokaryotic MetRS enzymes were synthesized and observed to have inhibitory activity on the T. brucei MetRS (50% inhibitory concentration, <50 nM) and on bloodstream forms of T. brucei cultures (50% effective concentration, as low as 4 nM). Twenty-one compounds had a close correlation between enzyme binding/inhibition and T. brucei growth inhibition, indicating that they were likely to be acting on the intended target. The compounds had minimal effects on mammalian cell growth at 20 M, demonstrating a wide therapeutic index. The most potent compound was tested in the murine model of trypanosomiasis and demonstrated profound parasite suppression and delayed mortality. A homology model of the T. brucei MetRS based on other MetRS structures was used to model binding of the lead diaryl diamine compounds. Future studies will focus on improving the pharmacological properties of the MetRS inhibitors.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionsupporting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Selective Inhibitors of Methionyl-tRNA Synthetase Have Potent Activity against Trypanosoma brucei Infection in Mice

Shibata

Gillespie

Kelley

et al. 2011

Antimicrob Agents Chemother

125

View full text Add to dashboard Cite

show abstract

“…The challenge for MetRS inhibitors, however, is not biochemical activity but whole-cell activity. The most potent examples at the biochemical level, with IC 50 values in the low nanomolar range, including oxazolone dipeptides and methionyl adenylate isosteres, have shown good selectivity versus human MetRS but lack antibacterial activity in wholecell assays 8 . To date, REP3123 (Figure 1), a novel diaryldiamine, is the only documented selective C. difficile MetRS inhibitor with whole cell activity in a range of clinical C. diffcile isolates 9 .…”

Section: Introductionmentioning

confidence: 99%