A triple helix model for the structure of chromatin fiber

Abstract
A model of chromatin fiber structure is presented in which a repeating unit of a trinucleosome forms a 3‐dimensional zigzag. Twisting and compression of the zigzag result in a triple helix structure. The model is built mainly on the flow linear dichroism data showing that (a) nucleosomal disc faces are tilted relative to the fiber axis, (b) the orientation of nucleosomes does not change upon folding and unfolding of chromatin, and (c) the orientation of nucleosomes is maintained by the globular domain of histone HI.