(a) Ensemble of the 25 structures of AS1p-TarEc in 10% negatively charged phospholipid bicelles with the lowest CYANA target function. The side-chains of Pro6, Ile11, His13, Arg15, Ile17 and Gly19 from the average structure in the ensemble are shown. (b) AS1 of TarEc adopts an amphipathic α-helical structure in the presence of acidic bicelles. The position of the hydrophobic (yellow), postively charged (blue), negatively charged (red), and partially positively charged residues (grayish green) are indicated. The side chains of Lys9 and Arg15 that flank this region are indicated as well.