Bar chart showing the relative affinities of ifenprodil and RO25,6981 towards the three buffers' refolded 6 × His-ATD2B proteins. A. Results are the average of five experiments using proteins obtained from at least two independent batches of bacteria induction. Error bars represent S.E. Ratios of KD(ifenprodil) to KD(RO25,6981) are 9 (Buffer-9), 15 (Buffer-12) and 24 (Buffer-13), respectively. B. Composite antagonists' inhibition curves are shown for NR1 coexpressed with wild-type NR2B in Xenopus oocytes. Error bars represent ± SEM. C. The Log IC50 for RO25,6981, ifenprodil and haloperidol plotted against their respective Log KD values obtained from dose-titration using CD. A linear regression fit revealed good correlation (R = 0.96) between the mean Log IC50 and Log KD values for each ligand. The mean of the sum of individual log value obtained from each fitted dose-inhibition plot for each ligand and SEM are plotted. Mean KD and IC50 values are given in Table 1.