Figure 5.

Relationship between stability against unfolding, X_U, and stability against misfolding, X_M. (A) An inverse relationship between the two kinds of stabilities is observed in orthologous bacterial proteins. (B) The same relationship in simulated protein evolution. Each line corresponds to a different population size, N, and neutrality parameter, S; each point represents a mutation bias measured as the GC content that would be attained with mutation alone. Mutations favoring GC produce less hydrophobic proteins, which are more stable against misfolding, but less stable against misfolding, moving leftwards in the horizontal direction. Stability increases with population size N, but it becomes less dependent on both population size and mutation bias for large neutrality parameter S.