Displacement of radiolabeled 1-anilinonaphthalene 8-sulfonic acid from EFABP expressed in Escherichia coli BL21 (DE3) by fluorescence spectrophotometry
Displacement of 1,8-ANS from His6-tagged FABP5 (unknown origin) expressed in Escherichia coli BL21(DE3) cells at 25 uM by fluorescence assay relative to control
Displacement of Bodipy-labeled fatty acid from human N-terminal His6-tagged FABP5 (127 to 132 residues) expressed in Escherichia coli after 30 mins by TR-FRET assay
Time Resolved-Fluorescence Energy Transfer (TR-FRET) Assay: Stock DMSO solutions (1.8 mM) of compounds were serially diluted 3-fold for ten concentrations with 100% DMSO (50 uM to 0.003 uM final compound concentration). 1 ul of these compound dilutions and 1 ul of Bodipy labeled fatty acid 4.5 uM in 100% DMSO (Bodipy FL C11, cat. no. D3862, Invitrogen) were sequentially pipetted in wells of 384-well black polypropylene plates (Thermo Matrix cat. no. 4344). FABP4 or FABP5 protein was then added (28 ul of 64 nM protein in 25 mM Tris pH 7.5, 0.4 mg/ml γ-globulin, 1 mM DTT, 0.012% NP40, final protein concentration: 50 nM). Assay blanks contained ligand, but no protein. Neutral controls contained ligand, but no compound. After adding the detection reagent (Tb antiHis6 antibody, Columbia Biosciences, TB-110, 6 ul of a 24 nM Ab solution in 25 mM Tris pH 7.5, 0.4 mg/ml γ-globulin, final Tb antiHis6 Ab concentration: 4 nM), plates were spun one minute at 1000 rpm. Following an incubation at room temperature with shaking for 30 minutes, plates were read using an Envision reader (Perkin Elmer, Extinction wavelength: 340 nm, Emission: 490 nm and 520 nm, time delay: 100 us; time window: 200 us, 50 flashes). Final assay conditions were: 50 nM FABP protein, 125 nM Bodipy labeled fatty acid, 0.009% (vol/vol) NP40, 5.5% (vol/vol) DMSO in a total final assay volume of 36 ul. The assay was performed in triplicate.
Time Resolved-Fluorescence Energy Transfer (TR-FRET) Assay: Stock DMSO solutions (1.8 mM) of compounds were serially diluted 3-fold for ten concentrations with 100% DMSO (50 μM to 0.003 μM final compound concentration). 1 μl of these compound dilutions and 1 μl of Bodipy labeled fatty acid 4.5 μM in 100% DMSO (Bodipy FL C11, cat. no. D3862, Invitrogen) were sequentially pipetted in wells of 384-well black polypropylene plates (Thermo Matrix cat. no. 4344). FABP4 or FABP5 protein was then added (28 μl of 64 nM protein in 25 mM Tris pH 7.5, 0.4 mg/ml α-globulin, 1 mM DTT, 0.012% NP40, final protein concentration: 50 nM). Assay blanks contained ligand, but no protein. Neutral controls contained ligand, but no compound. After adding the detection reagent (Tb antiHis6 antibody, Columbia Biosciences, TB-110, 6 μl of a 24 nM Ab solution in 25 mM Tris pH 7.5, 0.4 mg/ml γ-globulin, final Tb antiHis6 Ab concentration: 4 nM), plates were spun one minute at 1000 rpm.
Displacement of 1,8-ANS from human recombinant full length N-terminal his-tagged FABP5 expressed in Escherichia coli BL21 (DE3) at 25 uM incubated for 3 mins by fluorescence based assay relative to control
Displacement of 1,8-ANS from human recombinant full length N-terminal his-tagged FABP5 expressed in Escherichia coli BL21 (DE3) incubated for 3 mins by fluorescence based assay
Displacement of 1,8-ANS from human recombinant full length N-terminal his-tagged FABP5 expressed in Escherichia coli BL21 (DE3) assessed as inhibition of fluorescence at 100 uM incubated for 3 mins by fluorescence based assay relative to control
Displacement of 1,8-ANS from recombinant human 6His-tagged FABP5 expressed in Escherichia coli BL21 DE3 incubated for 15 mins followed by 1,8-ANS addition and measured after 3 mins by fluorescence based assay
Covalent binding affinity to FABP5 at Cys67 residue in human NCI-H358 cells assessed as log2 H/L ratio at 10 uM pretreated for 3 hrs followed by N-(((6S,7R)-7-(4-chloro-3-fluorophenyl)-1,4-oxazepan-6-yl)methyl)-2-hydroxyacetamide treatment for 3 hrs by competitive TMT click chemistry pull-down experiment based LC-MS/MS analysis