The synchrotron data do not only illustrate a rise in intensity at the bilayer center but also at approximately z = ± 11.1 Å , which does not occur in the higher resolution in-house study (Fig. 10b, d) . These peak positions may still be commensurate with more than one orientation, for example either a membrane-spanning orientation of the b-hairpin (Fig. 11i) or an orientation of the peptide species parallel to the membrane surface (Fig. 11ii) at the bilayer center. The latter is, however, not very likely for energetic reasons. (1/47.5/2.5) from diffuse anomalous scattering (a) and inhouse reflectivity (c). In the inhouse experiments the samples containing the iodine-labeled compound 7 were compared to the samples lacking the iodine probes (compound 2, black curve). The electron density difference curves (blue, shifted for clarity) are depicted for all peptide constructs 5, 7, and 8 either studied by synchrotron radiation (b) or by in-house reflectivity (d). The curves derived from in-house measurements are multiplied by a factor of 3 for clarity; the headgroup region is highlighted (green area)