Figure 3.

Variable-temperature 1D ¹³C MAS spectra of site-specifically labeled M2 peptides in lipid bilayers. (a) POPC/POPG (3:1)-bound M2(50–71). At 298 K, the peptide signals are weak in the CP spectrum but much stronger in the DP spectrum, indicating high mobility. At 253 K, the spectrum is severely broadened, consistent with the unstructured nature of this peptide. (b) DMPC-bound M2(22–71). The low-temperature spectrum shows narrow linewidths for the TM residues but broad linewidths for the cytoplasmic residues. At high temperature, the TM residues give high signals in the CP spectrum but low intensities in the DP spectrum, indicating their relative rigidity. (c) VM + bound M2(22–71). The chemical shifts and linewidths are similar to the DMPC-bound M2(22–71).