In model (A), the CTD of H1 initiates the binding interacting non-specifically with the linker DNA in an electrostatically driven association. In model (B), the WHD, stereospecifically through its S1- and S2-binding sites (orange circles), interacts first with the linker DNA at its entry and exiting regions in the nucleosome. In model (C), the WHD–CTD interact simultaneously with the linker DNA region, forming an electrostatic clamp. The double arrows indicate that the association of linker histones (histone H1) is a highly reversible process, as visualized in Figure 5. Reproduced from [17]: Raghuram, N., Carrero, G., Th’ng, J. and Hendzel, M.J. (2009) Molecular dynamics of histone H1. Biochem. Cell. Biol. 87, 189–206 with permission from Nuclear Regulatory Commission.