Fig. 1.

(a) Sequence space entropy as a function of energy, measured in difference from its maximum value, for one structure of high contact trace (diamonds) and one of low (circles). The higher trace structure clearly admits a greater number of low-energy sequences (gray shaded region), which in turn leads to a larger number of sequences (obtained by a Monte Carlo design procedure) having the structure as their ground state and to a larger fraction of those sequences having substantial gaps between their ground state and first excited, structurally dissimilar state energies (Inset). Such structures can therefore accommodate a much larger number of foldable, highly thermo-stable sequences. (b) Representative cubic lattice structures of high (Left) and low (Right) contact trace. The higher trace conformations exhibit a marked tendency toward greater structural regularity and symmetry.