Sequence Similarity : Non-homologous sequences (<30%) SEQUENCE SIMILARITY (%) 1l5aA 2d4uA 2d4uB 1l5aA 100 0 0 2d4uA 56 100 51 2d4uB 0 94 100 FOLD SIMILARITY (Z-SCORE) 1l5aA 2d4uA 2d4uB 1l5aA 65.6 0 0 2d4uA 0 26.8 12.3 2d4uB 0 24.4 27.1