Sequence Similarity : Non-homologous sequences (<30%) SEQUENCE SIMILARITY (%) 4r81A 4w66A 4w66B 4r81A 100 18 8 4w66A 16 100 93 4w66B 8 93 100 FOLD SIMILARITY (Z-SCORE) 4r81A 4w66A 4w66B 4r81A 38.2 0 0 4w66A 0 43.2 37.5 4w66B 0 37.5 41.3