874 research outputs found
An Efficient Way to Screen Inhibitors of Energy-Coupling Factor (ECF) Transporters in a Bacterial Uptake Assay
Herein, we report a novel whole-cell screening assay using Lactobacillus casei as a model
microorganism to identify inhibitors of energy-coupling factor (ECF) transporters. This promising
and underexplored target may have important pharmacological potential through modulation of
vitamin homeostasis in bacteria and, importantly, it is absent in humans. The assay represents an
alternative, cost-effective and fast solution to demonstrate the direct involvement of these membrane
transporters in a native biological environment rather than using a low-throughput in vitro assay
employing reconstituted proteins in a membrane bilayer system. Based on this new whole-cell
screening approach, we demonstrated the optimization of a weak hit compound (2) into a small
molecule (3) with improved in vitro and whole-cell activities. This study opens the possibility to
quickly identify novel inhibitors of ECF transporters and optimize them based on structure–activity
relationships
Search for the active ingredients from a 2-aminothiazole DMSO stock solution with antimalarial activity
Chemical decomposition of DMSO stock solutions is a common incident that can mislead biological screening campaigns. Here, we share our case study of 2-aminothiazole 1, originating from an antimalarial class that undergoes chemical decomposition in DMSO at room temperature. As previously measured biological activities observed against Plasmodium falciparum NF54 and for the target enzyme Pf IspE were not reproducible for a fresh batch, we tackled the challenge to understand where the activity originated from. Solvent- and temperature-dependent studies using HRMS and NMR spectroscopy to monitor the decomposition led to the isolation and in vitro evaluation of several fractions against Pf IspE. After four days of decomposition, we successfully isolated the oxygenated and dimerised compounds using SFC purification and correlated the observed activities to them. Due to the unstable nature of the two isolates, it is likely that they undergo further decomposition contributing to the overall instability of the compound
Recommended from our members
Bacteriomimetic Liposomes Improve Antibiotic Activity of a Novel Energy-Coupling Factor Transporter Inhibitor
Liposomes have been studied for decades as nanoparticulate drug delivery systems for cytostatics, and more recently, for antibiotics. Such nanoantibiotics show improved antibacterial efficacy compared to the free drug and can be effective despite bacterial recalcitrance. In this work, we present a loading method of bacteriomimetic liposomes for a novel, hydrophobic compound (HIPS5031) inhibiting energy-coupling factor transporters (ECF transporters), an underexplored antimicrobial target. The liposomes were composed of DOPG (18:1 (Δ9-cis) phosphatidylglycerol) and CL (cardiolipin), resembling the cell membrane of Gram-positive Staphylococcus aureus and Streptococcus pneumoniae, and enriched with cholesterol (Chol). The size and polydispersity of the DOPG/CL/± Chol liposomes remained stable over 8 weeks when stored at 4 °C. Loading of the ECF transporter inhibitor was achieved by thin film hydration and led to a high encapsulation efficiency of 33.19% ± 9.5% into the DOPG/CL/Chol liposomes compared to the phosphatidylcholine liposomes (DMPC/DPPC). Bacterial growth inhibition assays on the model organism Bacillus subtilis revealed liposomal HIPS5031 as superior to the free drug, showing a 3.5-fold reduction in CFU/mL at a concentration of 9.64 µM. Liposomal HIPS5031 was also shown to reduce B. subtilis biofilm. Our findings present an explorative basis for bacteriomimetic liposomes as a strategy against drug-resistant pathogens by surpassing the drug-formulation barriers of innovative, yet unfavorably hydrophobic, antibiotics
Bacteriomimetic Liposomes Improve Antibiotic Activity of a Novel Energy-Coupling Factor Transporter Inhibitor
Liposomes have been studied for decades as nanoparticulate drug delivery systems for
cytostatics, and more recently, for antibiotics. Such nanoantibiotics show improved antibacterial
efficacy compared to the free drug and can be effective despite bacterial recalcitrance. In this work,
we present a loading method of bacteriomimetic liposomes for a novel, hydrophobic compound
(HIPS5031) inhibiting energy-coupling factor transporters (ECF transporters), an underexplored
antimicrobial target. The liposomes were composed of DOPG (18:1 (∆9-cis) phosphatidylglycerol)
and CL (cardiolipin), resembling the cell membrane of Gram-positive Staphylococcus aureus and
Streptococcus pneumoniae, and enriched with cholesterol (Chol). The size and polydispersity of
the DOPG/CL/± Chol liposomes remained stable over 8 weeks when stored at 4 ◦C. Loading of
the ECF transporter inhibitor was achieved by thin film hydration and led to a high encapsulation
efficiency of 33.19% ± 9.5% into the DOPG/CL/Chol liposomes compared to the phosphatidylcholine
liposomes (DMPC/DPPC). Bacterial growth inhibition assays on the model organism Bacillus subtilis
revealed liposomal HIPS5031 as superior to the free drug, showing a 3.5-fold reduction in CFU/mL
at a concentration of 9.64 µM. Liposomal HIPS5031 was also shown to reduce B. subtilis biofilm.
Our findings present an explorative basis for bacteriomimetic liposomes as a strategy against drug resistant pathogens by surpassing the drug-formulation barriers of innovative, yet unfavorably
hydrophobic, antibiotics
Targeting the IspD enzyme in the MEP pathway: identification of a novel fragment class
Enzymes of the 2-C-methylerythritol-d-erythritol 4-phosphate 2C-methyl-D-erythritol 4-phosphate (MEP) pathway (MEP pathway or non-mevalonate pathway) are responsible for the synthesis of universal precursors of the huge large and structurally diverse family of isoprenoids. This pathway is absent in humans, but present in many pathogenic organisms and plants, making it an attractive source of drug targets. Here, we present a high-throughput screening approach that led to the discovery of a novel fragment hit active against the third enzyme of the MEP pathway, PfIspD. A systematic SAR investigation afforded a novel chemical structure with a balanced activity-stability profile (16). Using a homology model of PfIspD, we proposed a putative binding mode for our newly identified inhibitors that sets the stage for structure-guided optimization
Targeting the IspD Enzyme in the MEP Pathway: Identification of a Novel Fragment Class
The enzymes of the 2-C-methylerythritol-d-erythritol 4-phosphate (MEP) pathway (MEP pathway or non-mevalonate pathway) are responsible for the synthesis of universal precursors of the large and structurally diverse family of isoprenoids. This pathway is absent in humans, but present in many pathogenic organisms and plants, making it an attractive source of drug targets. Here, we present a high-throughput screening approach that led to the discovery of a novel fragment hit active against the third enzyme of the MEP pathway, PfIspD. A systematic SAR investigation afforded a novel chemical structure with a balanced activity–stability profile (16). Using a homology model of PfIspD, we proposed a putative binding mode for our newly identified inhibitors that sets the stage for structure-guided optimization
Search for the Active Ingredients from a 2-Aminothiazole DMSO Stock Solution with Antimalarial Activity
Chemical decomposition of DMSO stock solutions is a common
incident that can mislead biological screening campaigns. Here,
we share our case study of 2-aminothiazole 1, originating from
an antimalarial class that undergoes chemical decomposition in
DMSO at room temperature. As previously measured biological
activities observed against Plasmodium falciparum NF54 and for
the target enzyme PfIspE were not reproducible for a fresh
batch, we tackled the challenge to understand where the
activity originated from. Solvent- and temperature-dependent
studies using HRMS and NMR spectroscopy to monitor the
decomposition led to the isolation and in vitro evaluation of
several fractions against PfIspE. After four days of decomposition, we successfully isolated the oxygenated and dimerised
compounds using SFC purification and correlated the observed
activities to them. Due to the unstable nature of the two
isolates, it is likely that they undergo further decomposition
contributing to the overall instability of the compound
- …