Sequence Similarity : Non-homologous sequences (<30%) SEQUENCE SIMILARITY (%) 1is8A 1is8L 6chuA 1is8A 100 0 39 1is8L 28 100 26 6chuA 55 26 100 FOLD SIMILARITY (Z-SCORE) 1is8A 1is8L 6chuA 1is8A 32.4 0 0 1is8L 0.2 20.5 0 6chuA 0 0 45.5