CHEMBL5738495

HTS Assay: The conditions of the assay are as follows:Microplate type: 1536 Well Black Round Bottom Polystyrene Not Treated (Corning cat no. 3936)Total reaction volume: 5 μLMRE11 concentration in the reaction: 18 nMDNA substrate concentration in the reaction: 40 nMNumber of compounds to test: 257Inhibitor concentration range tested: 7 nM-50 μMMultiplicates: 3Concentration points: 13Dilution step: 2.1Each plate contains a series of high and low signal control wells, where no compound is added:High signal: MRE11+DNA substrateLow signal: DNA substrate onlyThese are used during data evaluation.Two Extra Assay Controls:1) To check whether unwinding of DNA by the compounds alone occurs.The DNA substrate [CY5+BBQ(650)] is mixed with the compounds with no protein present.This is done as a single measurement at 25 μM inhibitor concentration.2) To check whether the compounds are able to quench the CY5.The CY5 single stranded oligo is mixed with the compounds with no protein present. This is done as a single measurement at 25 μM inhibitor concentration.The layout of the plates is created by the in-house software (CZ-Openscreen Prague) and this information is transferred to the robotic HTS station.Assay Steps1) Prepare 50 mL of master mix:16.7 mL 5× reaction buffer (150 mM Bis Tris pH 7; 5 mM DTT)1042 μL 400 mM MnCl232.3 mL H2O2) Fill the plates with 3 μL of master mix per well using MultiDrop (Thermo Scientific)3) Transfer of compounds to the plates at the robotic station with the contactless Echo dispenser (Labcyte)4) Measurement of autofluorescence with the EnVision reader (PerkinElmer)5) Prepare 20 mL of 90 nM MRE11 in T+50 buffer (25 mM Tris-HCl pH7.5, 50 mM KCl 8.7% glycerol, 0.5 mM EDTA)6) Add 1 μL of 90 nM MRE11 to the corresponding wells using MultiDrop7) Preincubation at RT for 30 min8) Prepare 20 mL of a 200 nM solution of 5′ overhang DNA substrate: 480 μL 6 μM DNA+19.52 mL H2O9) Prepare 4 mL of a 200 nM solution of the single stranded DNA (oligo 1): 8 μL 100 μM DNA+4 mL H2O10) Add 1 μL of each 200 nM DNA solution to the corresponding wells with the MultiDrop11) Fluorescence measurement with the EnVision reader every 45 minutesFluorescence readout: CY5λex/em=620/665 nmAnalysis