Figure 8
Typical porcupine quill microdiffraction patterns. (a) Typical pattern of a highly ordered α-type zone in perpendicular geometry. (b) Pattern obtained in the outer moderately ordered α-type zone in parallel geometry. Strong and sharp diffraction arcs due to lipid stacks are clearly visible. Unexplained arcs at 7.1 and 3.5 Å can also be seen. The anisotropy of the 9.7 Å ring intensity indicates that fibres are not parallel to the incident beam, i.e. to the quill axis. (c) Pattern in the transition zone in perpendicular geometry; the 5.15 and 30 Å features have disappeared. (d) Pattern in the middle zone in perpendicular geometry. A rather sharp arc at 4.65 Å, typical of poorly ordered β-type, is visible. |