Figure 5.

Screening of cell lysates to derive dissociation constant K_d and protein concentration. (A) Two HumRadA22 cell lysates were titrated into 100 (blue) and 20 nM (red) BRC4^fl. (B) Each curve fit results in a linear relationship between dissociation constant (K_d) and protein concentration ([HumRadA22]^lysate). The intersection of the lines gives the only K_d and protein concentration value that solves both line equations derived from the titrations at 100 and 20 nM, respectively. (C) Example fits taken along the two correlation lines of (B). Only the intersect point denoted I gives an accurate fit for both curves ([HumRadA22]^lysate = 653 ± 15 nM, K_d = 11 ± 0.5 nM).