The Molecular Architecture for the Intermediate Filaments of Hard Alpha-Keratin Based on the Superlattice Data Obtained from a Study of Mammals Using Synchrotron Fibre Diffraction

The study used synchrotron fibre diffraction to analyze hard α-keratin from 27 mammalian samples, confirming a universal model for its molecular architecture. It identified a superlattice structure with two infinite lattices and three finite lattices, supporting the helices within helices model where dimers form tetramers around intermediate filaments. The research validated the structure proposed by Feughelman and James, showing that the center-to-center spacing of intermediate filaments was three times their radius, with a significant infinite lattice spacing of 62.6 nm. The findings suggested this architectural arrangement might be universal across various hard α-keratin tissues.