Neurofilaments from ox spinal nerves. Isolation, disassembly, reassembly and cross-linking properties

Abstract

An isolation procedure for neurofilaments from ox spinal nerves is described where the triplet polypeptides (which have molecular weights of 205,000, 158,000 and 72,000) constitute more than 80% of the preparation. Soon after purification, the neurofilaments form a gel that is stable for many weeks. The purified neurofilaments disassemble in low-salt buffers at pH > 7.0 into soluble particles that contain all of the triplet polypeptides. Greater than 90% of the protein can reassemble to form filaments. The thiol-containing residues in the filaments can be cross-linked. Analyses of the complexes formed show that in the filament the 205,000-mol.wt. components are arranged so that they can be cross-linked to themselves and to the 158,000-mol.wt. polypeptides, and that the 72,000-mol.wt. components are arranged so that their thiol groups can be cross-linked together.