Cross-linking of DNA Segments by Histone H1 Explains H1 Associated Phenomena of Chromatin Folding

Molecular mechanism for the cooperative and non-cooperative binding of histone H1 to DNA, its rearrangement and exchange between chromatin fibers and its role in the folding of interphase chromatin are proposed in this communication. The mechanism of H1 binding to DNA described here is simple and is based on two established facts; (i) histone H1 can crosslink two DNA segments through salt bridge formation between its positively charged lysine and arginine residues and the negatively charged phosphodiester bonds of the DNA segments, (ii) cations reduce the negative charges on DNA segments and thus decrease the force of repulsion between them.