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BioAssay: AID 541281

Activity of Bacillus stearothermophilus MetRS by ATP:PPi exchange assay in presence of ATP

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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 Tested Compounds
 Tested Compounds
All(1)
 
 
Active(1)
 
 
 Tested Substances
 Tested Substances
All(1)
 
 
Active(1)
 
 
 Related BioAssays
 Related BioAssays
AID: 541281
Data Source: ChEMBL (689807)
Depositor Category: Literature, Extracted
BioAssay Version:
Deposit Date: 2011-09-18
Modify Date: 2013-11-17

Data Table ( Complete ):           Active    All
Target
Sequence: RecName: Full=Methionine--tRNA ligase; AltName: Full=Methionyl-tRNA synthetase; Short=MetRS
Description ..   
Protein Family: catalytic core domain of methioninyl-tRNA synthetases
Comment ..   

Related Protein 3D Structures     More BioActivity 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.

Categorized Comment
ChEMBL Assay Type: Binding

ChEMBL Assay Data Source: Scientific Literature

ChEMBL Target ID: 103824

ChEMBL Target Type: Target is a single protein chain

Result Definitions
TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
1Km*Km PubChem standard valueFloatμM
2Km activity commentKm activity commentString
3Km standard flagKm standard flagInteger
4Km qualifierKm qualifierString
5Km published valueKm published valueFloatμM
6Km standard valueKm standard valueFloatnM

* Activity Concentration.

Data Table (Concise)
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