Fig. 8.

Comparison between the dependence of effective elastic potential of a spectrin bond on its length X presented for a worm-like chain potential by Li et al. (2013) (Eq. 1) (dashed curve) and the harmonic potential exhibiting the same second derivative of the potential at its minimum (Eq. 1) (solid curve). The constants of the chain term are taken from Discher et al. (1998) to be X₀ = 75 nm, X_max = 3.17X₀, and the persistence length is b = 0.075X₀. The parameter k_p obtained to give the minimum of the potential at X₀ is 1.82 10⁻³⁴ J/m². Second derivatives of both potential functions correspond to the spring constant K = 25.1 μN/m