Figure 5.

The cutoff model. (A) Electrostatic energy for a charge q₁ = 1 e at (0,4) Å and q₂ = ‒1 e at (x,z) Å. (B) Schematic illustration of the cutoff model. At one anchor position, the charge q₂ is attracted to q₁, independent of the stalk length l (i). At another anchor position, the charge q₂ is attracted to the extracellular solution, independent of the stalk length (ii). At certain anchor positions, the charge q₂ is attracted either to q₁ for shorter stalk lengths (iii) or to the extracellular solution for longer stalk lengths (iv). (C) Critical stalk lengths (i.e., the length at which the charge q₂ is attracted equally well to the charge q₁ or to the extracellular solution) for a stalk fixed at (x,z) Å. Charge q₁ = 1 e at d = (0,2), (0,4), (0,6) Å and q₂ = ‒1 e at the end of the stalk with different lengths (according to the color coding). (D) Positions for the cutoff anchor point when the stalk length is 4 Å (l = 4 Å). Charge q₁ = 1 e at d = (0,2), (0,4), (0,6) Å and q₂ = ‒1 e at the end of the stalk.