Sequence Similarity : Non-homologous sequences (<30%) SEQUENCE SIMILARITY (%) 4ekxA 4ekxC 4mtdA 4mtdD 4ekxA 100 99 29 0 4ekxC 99 100 31 0 4mtdA 26 27 100 99 4mtdD 0 0 99 100 FOLD SIMILARITY (Z-SCORE) 4ekxA 4ekxC 4mtdA 4mtdD 4ekxA 23.3 21.8 0 0 4ekxC 21.8 23 0 0 4mtdA 0 0 27.4 22.3 4mtdD 0 0 22.3 27.8