Sequence Similarity : Non-homologous sequences (<30%) SEQUENCE SIMILARITY (%) 2fbiA 2yf4A 2yf4B 2fbiA 100 71 0 2yf4A 68 100 97 2yf4B 68 97 100 FOLD SIMILARITY (Z-SCORE) 2fbiA 2yf4A 2yf4B 2fbiA 25 1.9 0 2yf4A 1.9 21.2 19.5 2yf4B 1.5 19.5 21.2