Direct Evidence Supporting the Existence of a Helical Dislocation in Protofilament Packing in the Intermediate Filaments of Oxidized Trichocyte Keratin

The study provided direct evidence supporting the existence of a helical dislocation in the intermediate filaments (IF) of oxidized trichocyte keratin. It demonstrated that during the assembly of trichocyte IF, the formation of disulfide linkages disrupted the structure present in the reduced state, leading to a helical dislocation similar to that found in certain microtubular structures. The research used a 1-D Patterson projection to confirm the presence of a surface lattice with specific dimensions, reinforcing previous proposals about the structural changes occurring between reduced and oxidized states. The findings highlighted that the end domains of IF molecules in the oxidized structure were in closer proximity than in the reduced structure.