Toward New Therapeutics for Skin and Soft Tissue Infections: Propargyl-Linked Antifolates Are Potent Inhibitors of MRSA and Streptococcus pyogenes

Viswanathan, Kishore; Frey, Kathleen M.; Scocchera, Eric W.; Martin, Brooke D.; Swain, P. Whitney; Alverson, Jeremy B.; Priestley, Nigel D.; Anderson, Amy C.; Wright, Dennis L.

doi:10.1371/journal.pone.0029434

Cited by 35 publications

(65 citation statements)

References 31 publications

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“…Bacterial cultures were grown with aeration at 37°C in Iso-sensitest broth (ISB) from Oxoid. Compounds 1 and 2 were synthesized as described previously (1,36). Trimethoprim (TMP) was purchased from Sigma-Aldrich.…”

Section: Methodsmentioning

confidence: 99%

“…These losses in potency are quite dramatic compared to the minimal losses observed for the Sa (F98Y) DHFR mutant and compound 1. In order to understand the greater effect imparted by F98I, we examined the structure of the wild-type enzyme (Protein Data Bank [PDB] code 3SGY) (36). Figure 3 represents the active site of the wild-type enzyme bound to compound 1 and NADPH, with residues His30 and Phe98 highlighted in orange.…”

Section: Evaluation Of Resistant Strains Lacking Point Mutations In Dmentioning

confidence: 99%

“…1). Several representative compounds from this series are potent inhibitors of the wild-type DHFR enzyme (IC 50 s range from 12 to 26 nM) and several clinically isolated MRSA strains (MIC values between 0.02 and 2.8 g/ml) (36). Four of the pyridyl-containing compounds have been shown to retain potency against a TMP-resistant strain, with an MIC value of 0.09 g/ml (36).…”

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confidence: 99%

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Prospective Screening of Novel Antibacterial Inhibitors of Dihydrofolate Reductase for Mutational Resistance

Frey

Viswanathan

Wright

et al. 2012

Antimicrob Agents Chemother

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Resistance to trimethoprim (TMP) resulting from point mutations in the enzyme drug target dihydrofolate reductase (DHFR) drives the development of new antifolate inhibitors effective against methicillin-resistant Staphlococcus aureus (MRSA). For the past several years we have used structure-based design to create propargyl-linked antifolates that are highly potent antibacterial agents. In order to focus priority on the development of lead compounds with a low propensity to induce resistance, we prospectively evaluated resistance profiles for two of these inhibitors in an MRSA strain. By selection with the lead inhibitors, we generated resistant strains that contain single point mutations F98Y and H30N associated with TMP resistance and one novel mutation, F98I, in DHFR. Encouragingly, the pyridyl propargyl-linked inhibitor selects mutants at low frequency (6.85 ؋ 10 ؊10 to 1.65 ؋ 10 ؊9 ) and maintains a low MIC (2.5 g/ml) and a low mutant prevention concentration (1.25 g/ml), strongly supporting its position as a lead compound. Results from this prospective screening method inform the continued design of antifolates effective against mutations at the Phe 98 position. Furthermore, the method can be used broadly to incorporate ideas for overcoming resistance early in the development process.

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Section: Methodsmentioning

confidence: 99%

Section: Evaluation Of Resistant Strains Lacking Point Mutations In Dmentioning

confidence: 99%

mentioning

confidence: 99%

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Prospective Screening of Novel Antibacterial Inhibitors of Dihydrofolate Reductase for Mutational Resistance

Frey

Viswanathan

Wright

et al. 2012

Antimicrob Agents Chemother

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“…The synthesis and characterization of compound 1 have been described (5). Trimethoprim is commercially available (Sigma-Aldrich).…”

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confidence: 99%

Protein design algorithms predict viable resistance to an experimental antifolate

Reeve

Gainza²,

Frey

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Methods to accurately predict potential drug target mutations in response to early-stage leads could drive the design of more resilient first generation drug candidates. In this study, a structurebased protein design algorithm (K* in the OSPREY suite) was used to prospectively identify single-nucleotide polymorphisms that confer resistance to an experimental inhibitor effective against dihydrofolate reductase (DHFR) from Staphylococcus aureus. Four of the top-ranked mutations in DHFR were found to be catalytically competent and resistant to the inhibitor. Selection of resistant bacteria in vitro reveals that two of the predicted mutations arise in the background of a compensatory mutation. Using enzyme kinetics, microbiology, and crystal structures of the complexes, we determined the fitness of the mutant enzymes and strains, the structural basis of resistance, and the compensatory relationship of the mutations. To our knowledge, this work illustrates the first application of protein design algorithms to prospectively predict viable resistance mutations that arise in bacteria under antibiotic pressure.drug resistance | antifolate | protein design | DHFR | MRSA

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“…Various synthetic analogs of diaminopyrimidine, including iclaprim, have been developed via three-dimensional structure-based rational design 3,17) Iclaprim is a promising antibacterial drug, which is currently being tested in a Phase III clinical trial. Recently, the discovery of new scaffolds for nonclassical DHFR inhibitors, including thiazoles, 18) quinolinones, 19) and propargyl-linked compounds 20,21) have been reported. Cytotoxic puupehenone (sesquiterpene hydroquinone) and bastadin from the Verongid sponges were reported to inhibit mammalian DHFR.…”

Section: Resultsmentioning

confidence: 99%

The Lactone Form of Stachybotrydial: A New Inhibitor of Dihydrofolate Reductase from <i>Stachybotrys</i> sp. FN298

Kwon

Sohn

Kim

et al. 2014

Biological & Pharmaceutical Bulletin

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Dihydrofolate reductase (DHFR) has been confirmed to be a novel target for antibacterial drug development. In this study, we determined that a fungal metabolite from Stachybotrys sp. FN298 can inhibit the DHFR of Staphylococcus aureus. Its structure was identified as a lactone form of stachybotrydial using mass spectrometry and nuclear magnetic resonance analysis. This compound inhibited S. aureus DHFR with a half-maximal inhibitory concentration of 41 µM. It also prevented the growth of S. aureus and methicillinresistant S. aureus (MRSA) with a minimum inhibitory concentration of 32 µg·mL 1 . To our knowledge, this is the first description of a DHFR inhibitor of microbial origin. The inhibitory function of the lactone form of stachybotrydial highlights its potential for development into a new broad-spectrum antibacterial agent and as an agent against MRSA.

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Toward New Therapeutics for Skin and Soft Tissue Infections: Propargyl-Linked Antifolates Are Potent Inhibitors of MRSA and Streptococcus pyogenes

Cited by 35 publications

References 31 publications

Prospective Screening of Novel Antibacterial Inhibitors of Dihydrofolate Reductase for Mutational Resistance

Prospective Screening of Novel Antibacterial Inhibitors of Dihydrofolate Reductase for Mutational Resistance

Protein design algorithms predict viable resistance to an experimental antifolate

The Lactone Form of Stachybotrydial: A New Inhibitor of Dihydrofolate Reductase from <i>Stachybotrys</i> sp. FN298

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