Fig. 5.

Two-state behavior is preserved for sequences with blocks of oppositely charged residues. (A) Amino acid sequences of sv5 and sv10. (B and C) The distributions P(x) computed for two sequences designated as sv5 and sv10. The corresponding free energy profiles of B and C are shown in SI Appendix, Fig. S14. (B) P(x) for sv5 shows that the two-state behavior is preserved for sequences with mild degrees of segregation of oppositely charged residues. (C) P(x) for sv10 shows that there are temperatures where intermediate states, corresponding to well-defined metastable structures, become prominent as the linear segregation of oppositely charged residues increases. (D) Four Ω-loop-like structures observed as stable intermediates for sv10. The structures were extracted from simulations performed at 340 K and were drawn using VMD. Lys is in blue and Glu residues are in red.