Sequence Similarity : Non-homologous sequences (<30%) SEQUENCE SIMILARITY (%) 1g99A 4fdfA 4fdfB 1g99A 100 13 11 4fdfA 0 100 97 4fdfB 11 97 100 FOLD SIMILARITY (Z-SCORE) 1g99A 4fdfA 4fdfB 1g99A 71.5 0 0 4fdfA 0 27.9 24 4fdfB 0 24 28.3