Figure 3: Well-folded mutants obtained by directed evolution.

(a–c) 1H–15N NMR heteronuclear single quantum coherence (HSQC) spectra of different well-folded mutants. (d) Types and locations of mutations in D_1cy5_M1 and D_1cy5_M2. Target secondary and tertiary structures are shown. Sticks represent original side chains at mutated positions. (e) Same as in d, but for Dv_1r26_M1.