Structural data for characteristic observed diffraction patterns.

The structure factors for the intensities measured by the microfocus beam are given by , and their scaling was determined by , where d is the lamellar period. The diffracting power P was measured according to the equation described in (Text S1). The intensity data for fresh, mouse sciatic nerve myelin were obtained from Figure 5 in Ref. (7). In the Table, the sample is indicated by the image number, and the scanning direction is indicated by E, for along the equator (lamellar stacks perpendicular to the vertical oriented nerve fiber; M, for along the meridian (lamellar stacks parallel to the vertically oriented nerve fiber), and 25deg, for 25° from the horizontal. The distance between the centers of membrane bilayers across the cytoplasmic apposition is given by 2u. Cyt, the width of the cytoplasmic apposition; Lpg, the distance between the lipid polar head group layers; Ext, the width of the extracellular apposition. The number of unit cells N, or coherent length, and lattice disorder Δ were calculated from , where w is the observed integral width for the hth reflection, and b is the integral width of the direct beam [54].