Fig. 6.

Combined current and fluorescence recording of rhodamine-labeled A52C and A52C–A248L mutant GlyRs reveals a conformational change specifically associated with receptor desensitization. The A248L mutation in the M1–M2 loop induces fast desensitization. a Examples of current (black) and fluorescence (red) responses induced by a saturating glycine concentration in both GlyRs. Note the biphasic fluorescence response and the glycine-induced plateau in the double mutant GlyR. b Averaged time constants for current and fluorescence decay recorded from double mutant GlyRs plotted as a function of glycine concentration. There was no significant difference at any concentration, confirming that the fluorescence response reported a conformational change associated with desensitization. Figure modified from [30]