Table 2. Dissociation Constants and Protein Concentrations Obtained from FA Measurements of Cell Lysates (SI, Figure S8)^a.

HumRadA	Kdb (nM)	Kdc (nM)	[HumRadA]d (nM)
HumRadA14	670 ± 12	910 ± 130	780 ± 110
HumRadA16	294 ± 6	250 ± 7	273 ± 8
HumRadA18	10.3 ± 0.4	17 ± 5	35 ± 4
HumRadA20	3.9 ± 0.2	15 ± 2	831 ± 30
HumRadA22	6.2 ± 0.3	11 ± 0.5	653 ± 15

^aConditions: CHES 20 mM, pH 9.5, 100 mM NaCl, 1 mM EDTA, 1% BSA, T = 24 °C. Two titrations were performed at 100 and 20 nM ligand BRC4^fl concentration, respectively, so that both K_d and expression levels were derived.

^bTaken from ref (19). K_d values determined with purified HumRadAs in microtiter plates.

^cMeasured by FA analysis in lysate screens, as described in this work.

^dConcentration in lysate and determined by the lysate screen described here. Standard deviations for droplets measurements were obtained from the global fit from one single experiment.