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BioAssay: AID 545000

Inhibition of Haemophilus influenzae MetRS

REP8839 is a selective inhibitor of methionyl-tRNA synthetase (MetRS) with antibacterial activity against a variety of gram-positive organisms. We determined REP8839 potency against Staphylococcus aureus MetRS and assessed its selectivity for bacterial versus human orthologs of MetRS. The inhibition constant (K(i)) of REP8839 was 10 pM for Staphylococcus aureus MetRS. Inhibition of MetRS by more ..
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Active(1)
 
 
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AID: 545000
Data Source: ChEMBL (693526)
BioAssay Type: Confirmatory, Concentration-Response Relationship Observed
Depositor Category: Literature, Extracted
BioAssay Version:
Deposit Date: 2011-09-18
Modify Date: 2014-08-23

Data Table ( Complete ):           View Active Data    View All Data
BioActive Compound: 1
Description:
Title: Inhibition of methionyl-tRNA synthetase by REP8839 and effects of resistance mutations on enzyme activity.

Abstract: REP8839 is a selective inhibitor of methionyl-tRNA synthetase (MetRS) with antibacterial activity against a variety of gram-positive organisms. We determined REP8839 potency against Staphylococcus aureus MetRS and assessed its selectivity for bacterial versus human orthologs of MetRS. The inhibition constant (K(i)) of REP8839 was 10 pM for Staphylococcus aureus MetRS. Inhibition of MetRS by REP8839 was competitive with methionine and uncompetitive with ATP. Thus, high physiological ATP levels would actually facilitate optimal binding of the inhibitor. While many gram-positive bacteria, such as Staphylococcus aureus, express exclusively the MetRS1 subtype, many gram-negative bacteria express an alternative homolog called MetRS2. Some gram-positive bacteria, such as Streptococcus pneumoniae and Bacillus anthracis, express both MetRS1 and MetRS2. MetRS2 orthologs were considerably less susceptible to REP8839 inhibition. REP8839 inhibition of human mitochondrial MetRS was 1,000-fold weaker than inhibition of Staphylococcus aureus MetRS; inhibition of human cytoplasmic MetRS was not detectable, corresponding to >1,000,000-fold selectivity for the bacterial target relative to its cytoplasmic counterpart. Mutations in MetRS that confer reduced susceptibility to REP8839 were examined. The mutant MetRS enzymes generally exhibited substantially impaired catalytic activity, particularly in aminoacylation turnover rates. REP8839 K(i) values ranged from 4- to 190,000-fold higher for the mutant enzymes than for wild-type MetRS. These observations provide a potential mechanistic explanation for the reduced growth fitness observed with MetRS mutant strains relative to that with wild-type Staphylococcus aureus.
(PMID: 19015366)
Comment
Compounds with activity <= 50uM or explicitly reported as active by ChEMBL are flagged as active in this PubChem assay presentation.

Putative Target:

ChEMBL Target ID: 103822
Target Type: SINGLE PROTEIN
Pref Name: Methionyl-tRNA synthetase
Synonyms: Methionine--tRNA ligase;Methionyl-tRNA synthetase;MetRS;
Gene Name: metG;
Protein Accession: P43828;
Protein GI: 1174532;
Organism: Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)
Tax ID: 71421
Target Classification: enzyme
Confidence: Homologous single protein target assigned
Relationship Type: Homologous protein target assigned
Categorized Comment - additional comments and annotations
From BioAssay Depositor:
Assay Type: Binding
Assay Data Source: Scientific Literature
Result Definitions
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TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
1Ki*Ki PubChem standard valueFloatμM
3BEIBinding Efficiency Index(nM)Float
2SEISurface Efficiency Index(nM)Float
4LELigand EfficiencyFloat
5LLELipophilic Ligand EfficiencyFloat
6Ki activity commentKi activity commentString
7Ki standard flagKi standard flagInteger
8Ki qualifierKi qualifierString
9Ki published valueKi published valueFloatnM
10Ki standard valueKi standard valueFloatnM

* Activity Concentration.

Data Table (Concise)
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