Abstract :
Neurofilaments NFs.are composed of neurofilament triplet proteins NFTPs., NF-L, NF-M and NF-H. The structure of
neurofilaments, isolated from bovine spinal cords, was studied with scanning tunneling microscope STM.. STM images of
NFs with relatively higher resolution were obtained for the first time. The results showed that NFs revealed as a kind of
periodic structure, composed of a long core filament 9–11 nm in diameter.and lateral sidearms projecting from the core
filament every 10 nm space. There were undulant structures on the surface of core filament. The periodicity along the core
filament was obtained from cross-section analysis. The periods along the axis and two sides of the core filament were
uniform to be about 10 nm. In some regions, there was also 20 nm periodicity, indicating the distance between two adjacent
long sidearms in the topography, which coincided with the periodic distribution of sidearms observed by metal shadowing
electron microscopy. However, the previous half-staggered model could not explain the 10-nm periodicity. According to the
results from STM experiments, it could be deduced that three-quarter-staggered organization of subunits must take place
during the assembly of native NFs. q1999 Elsevier Science B.V. All rights reserved.
