This report describes the use of digital correlation and averaging
methods 1,2 for the reconstruction of high dose
electron micrographs of the chitin-protein complex from
Megarhyssa ovipositor.
Electron microscopy of uranyl acetate stained insect cuticle has
demonstrated a hexagonal array of unstained chitin monofibrils, 2.4−3.0 nm
in diameter, in a stained protein matrix3,4. Optical
diffraction Indicated a hexagonal lattice with a = 5.1-8.3
nm3 A particularly well ordered complex is found in
the ovipositor of the ichneumon fly
Megarhyssa: the small angle x-ray data
gives a = 7.25 nm, and the wide angle pattern shows that the protein
consists of subunits arranged in a 61 helix, with an
axial repeat of 3.06 nm5.