Figure 1. Histogram potential for one-dimensional toy model.

Solid curves: discretized potential acting between two isolated spherical protein “subunits” as a function of the distance between sphere centers (r = r_g/2). Solid line: potential in the presence of 4 M urea. Dashed lines: attractive potential in bin 1 (see Table 1) calculated for c_urea = 1, 2 and 3 M. Dotted curve: continuous potential of mean force as a function of R_g, derived from the distribution of R_g of unfolded states of ribonuclease A calculated by Goldenberg [38] as described in Minton [15].