SPR screening was performed using Biacore 8K instruments at 20 °C. After conditioning both reference and active flow cells with 50 mM NaOH for 3 × 60 s with a flow rate of 10 μL/min, Biotinylated ctdWDR91 (392-747) and WDR12 (WDR) were immobilized on a SA sensor chip using four channels for each protein. Each protein solution (30 μg/mL) was injected through the respective active flow cells for 60 s with a flow rate of 5 μL/min for protein immobilization on the streptavidin coated (SA) sensor surface, which resulted in an immobilization level of ~4000-4500 RU. After protein immobilization in the active flow cells, equilibration was performed by flowing running buder (50 mM HEPES, pH 7.5, 150 mM NaCl, 0.001% Tween 20, 0.2% PEG3350, 0.5 mM TCEP, and 3% DMSO) over the flow cells with a flow rate of 50 μL/min until a stable baseline was observed. The compounds were then injected over the reference and active flow cells using multi-cycle kinetics at a flow rate of 40 μL/min with a 55 s association time and a 120 s dissociation time for both single concentration screening and dose-response titration Sudicient number of start-ups, blanks, solvent corrections, and wash (50% DMSO wash to flush the needles) cycles were included in the SPR methods during compound analysis. The compound dilution was performed in 100% DMSO with 2-fold serial dilution and prepared the samples using the running buder by maintaining the final DMSO concentration of 3% (v/v) across the tested concentration range. The compounds were titrated between 0-15 µM, 0-30 µM, and 0-45 µM compound concentrations based on the adinity and the solubility condition. Fivepoint solvent correction was included for each run to adjust high bulk responses from the solvent. Double referencing of the data was performed by subtraction of the reference flow cell and then the respective zero compound concentration cycles. Data analysis was performed using the Biacore Insight Evaluation software, and adinity fitting was performed by applying a 1:1 binding model provided with the software. The final figures were prepared by exporting the data to GraphPad Prism.