Figure 4.
Optimization of 1H to 15N cross-polarization as demonstrated for EmrE in lipid bicelles. (A) The 1H power is arrayed around a constant 15N amplitude used for cross-polarization. As seen from the spectra, a linear ramp of 41.7 ± 5.6 kHz gave the highest signal/noise for all experiments. These data show that a linear ramp improves the signal/noise and emphasizes the importance of optimizing cross-polarization.