Figure 4.

³¹P linewidths from a single pulse MAS experiment for EmrE embedded within 14:0-PC (A) and O-14:0-PC bilayers (E). The blue and red points correspond to EmrE in the absence and presence of TPP⁺, respectively. The black points correspond to the lipid only samples. Data reflect the average of two separate trials where the error bars represent the standard deviation of these datasets. The ³¹P linewidth vs. temperature plots for each trial are shown in Figure S3. Representative ³¹P spectra are shown at a temperature of 23 °C for 14:0-PC in the absence (B) and presence of TPP⁺ (C) and lipid only (D). The same is shown at 27 °C for O-14:0-PC in the absence (F) and presence of TPP⁺ (G) and lipid only (H). In both lipid compositions, there is a reduction in the ³¹P linewidth when EmrE is bound with TPP⁺. Note that the small peak around ~1 ppm is signal from the phosphate buffer used to prepare the samples.