FIGURE 4.

Sensitivity of residues predicted to reside at the opening of the pore to MTS reagents. HEK-293 cells transiently transfected with C109A and hSERT Cys mutant cDNAs were incubated with 1 mm MTSET (A) or 1 mm PMTS (B) for 10 min at room temperature, followed by [³H]5-HT uptake as described under “Experimental Procedures.” Bars, means ± S.E. (error bars) from three independent experiments performed in triplicate. Normalized data are presented for each mutant. *, p < 0.001 compared with C109A using a one-way analysis of variance with a post hoc Dunnett's test.