FIGURE 4.

The α1(K312E) mutation reduced relative efficacy of P4S. A, shown are structural similarities between full and partial agonists, GABA and P4S respectively. B, shown are averaged whole-cell current traces elicited with GABA (solid) and P4S (dashed) for WT and α1(K312E) receptor-containing cells; bars indicate agonist application with concentrations in μm. The same concentration range was used for full and partial agonists. C, the Hill equation fit of data normalized to the maximal GABA response showed a significant decrease in the relative agonist affinity ratio for the α1(K312E) mutation (open circles) compared with WT (solid circles); error bars denote S.E.; n = 3.