Corrections of the scattering distribution (dark image, polarization), normalization (monitor signal, counting time), and coordinate transformation to (q k , q z ) coordinates based on the calculated sample-to-detector distance led to the 2D intensity distribution in the reciprocal space (Fig. 4a) . Intensity profiles (Fig. 4b) of the cc peak were extracted by interpolation along radial sections through the reciprocal space (black lines in Fig. 4a ) for different angles / corresponding to the tilting of lipid acyl chains in real space (Fig. 4a, inset) . The root mean square deviation of the intensity was estimated via extraction of five neighboring profiles within a distance of D/ = 0.2°( 1-2 pixels). A Lorentzian function (Eq. 1) was fitted to the intensity traces via a nonlinear least squares method using a trust region.