Neurofilaments (NFs) were isolated from bovine spinal cord. The structure of purified NFs
was studied by scanning tunneling microscopy (STM) . The STM images showed that NF was composed
of a long core filament and numerous sidearms flanking the rod regularly. The diameter of the rod was
about 10 nm (10.2 f 0.8 nm) . Most of the sidearms were short and the distance between two adjacent
sidearms was approximately 10 nm. There were some long sidearms between two proximal core filaments.
The distance between two adjacent long sidearms was 21 nm. A three-quarter-staggered fashion
of native NF structure was put forward.