Black opaque 96 well plates

For direct IP readouts, 100 μL of bead samples were loaded in black opaque 96-well plates (PerkinElmer) and read in a fluorometric plate reader (CLARIOstar Plus, BMG Labtech). Optimal gain and focal height settings were adjusted to the brightest wells. A total of 81 fluorescence measurements were acquired throughout the entire area of each well (9 × 9 data point matrix scan). The average value of all measurements was considered per well. As beads did not interfere with measurements, nor contribute to background fluorescence, raw sample fluorescent signals were normalized to filtered PBS and data is presented as signal-to-noise (S/N) or as % of input. For indirect IP readouts, 200μL of the IP flow-through were measured in parallel with input controls (IPs lacking beads). As described above, settings were adjusted to the brightest wells, which in this case were always input controls. Indirect data points were presented as percentage of recovered input, determined as: $$\%ofinput(flowthrough)=1-\frac{IPflowthrough(S/N)}{input(S/N)}$$