Structural similarities and differences amongst neurofilaments.

Neurofilaments purified from cat, ox, Loligo and Myxicola nerve fibres are composed of different numbers of polypeptides with different molecular weights. Mammalian neurofilaments also differ from those of marine invertebrates by being about 20% larger in diameter. Despite the differences, X-ray diffraction patterns from all the neurofilaments indicate a common alpha-helical content with alpha-helices arranged in coiled-coils. The patterns from Myxicola neurofilaments also indicate a long-range periodicity along the length of these filaments which is of the order of 25.2 nm.