Table 1. Comparison of Dissociation Constants K_d Obtained from Fluorescence Anisotropy Measurements in Droplets (Droplets of 10–20 nL) and in a Titerplate (Well Volume: 100μL)^a.

Kd (nM)		dropletc (100 nM BRC4fl)
HumRadA variants	96-well plateb (10 nM BRC4fl)	repeat 1	repeat 2	avg	dropletc (5 nM BRC4fl)
HumRadA14	670 ± 12	2130 ± 100	1901 ± 22	2015 ± 102	not determined
HumRadA18	10.7 ± 0.4	32.9 ± 1.3	36.2 ± 1.4	34.5 ± 1.9	32.1 ± 0.4
HumRadA20	3.9 ± 0.2	14.6 ± 0.5	17.2 ± 0.2	15.9 ± 0.5	11.0 ± 0.2

^aConditions in titerplate measurements: 100 μL of 100 nM BRC4^fl at varying HumRadA concentrations; [CHES] = 20 mM, pH 9.5, 100 mM NaCl, 1 mM EDTA. Conditions in each droplet: 20 nL at 100 nM BRC4^fl at varying HumRadA concentrations; 20 mM, pH 9.5, 100 mM NaCl, 1 mM EDTA, 1% BSA. All measurements were performed at room temperature. Standard deviations come from the fitting algorithm based on a single titration.

^bSee ref (19).

^cSee curves in Figure 4a,b.