Comparison of a sample of observed and predicted OS ssNMR data from wild type constructs of the Influenza A M2 protein. (Red) Observed resonance frequencies for S31, H37, W41, L43, L46, F47, F55, and L59 from M2 (22–62) in liquid crystalline lipid bilayers used to define the 2L0J structure [80]. The letter designations are used only for the 2L0J resonances. (Purple) Predicted resonance frequencies from the solution NMR structure (2RLF) [83] in detergent micelles of M2 (19–61) for the same sites. (Green) Predicted resonance frequencies from the X-ray crystal structure (3BKD) [82] in detergent based crystals of M2 (22–46) for the same sites except for F47, F55, and L59 which were not in this construct. 3BKD is an asymmetric structure and hence the four helices give rise to different resonance frequencies. Different shades of green are used to color code the different helices in 3BKD. The data and predictions are plotted on an absolute scale for the dipolar coupling. Both the predications and data for F47, F55, and L59 are used in the structures as negative values.