FIGURE 4.
Removing or reversing the side chain charge of Arg-131 increases the efficacy of the partial agonist sarcosine on α1 GlyR. A, representative whole cell current responses to sarcosine in α1 GlyR mutants. B, clusters of single-channel mutant GlyR activity elicited in cell-attached patches by high concentrations of sarcosine (saturating except for the R131E mutant) C, sarcosine whole cell concentration-response curves for E103A, E103R, R131A, and R131E mutant GlyR (n = 4, 4, 5, and 6, respectively). Curves are scaled to the appropriate maximum Popen measured by single channel recording. The WT concentration-response curve for sarcosine is shown for comparison (solid line; the data for this curve is shown in Fig. 2C).