Sequence Similarity : Non-homologous sequences (<30%) SEQUENCE SIMILARITY (%) 2yxhA 2yxhB 4s28A 2yxhA 100 99 46 2yxhB 99 100 45 4s28A 0 0 100 FOLD SIMILARITY (Z-SCORE) 2yxhA 2yxhB 4s28A 2yxhA 18.6 17.3 0.8 2yxhB 17.3 18.5 0.6 4s28A 0 0 76.1