Extended Data Fig. 7: ETM pentameric models analyzed to disambiguate the direction of interhelical constraints used for structure calculation.

For each model, the heptad repeat positions (abcdefg) of every residue from L12 to T35 is indicated on the helical wheel for at least one subunit. On the two neighboring helices, residue positions that violate measured ¹³C-¹⁹F correlations are shown in pink, while residue positions that violate the water and lipid accessibility data are shown in green. The positions of Phe residues that satisfy the interhelical contacts are shown in blue. a, Model 1 places N15 at heptad position d without a twist, and is thus an ideal helix model. b, Model 2 places N15 at d with a twist such that F23 moves from position e to c. c, Model 3 places N15 at position e with a twist such that F23 moves from f to b. d, Model 4 places N15 at position a with a twist such that F23 moves from b to c. e, Model 5 places N15 at position a with a twist such that F23 moves from b to f. Model 5 does not violate any experimental data and was thus chosen to disambiguate intermolecular contacts for structure calculation. To make the interhelical contacts explicit, model 5 shows the residue positions for three consecutive helices in the pentamer.