The β-HCH degradation activities of LinB
, and their intermediate mutants. Specificity constants of LinBUT (vertical hexagon), LinBMI (circle), and their intermediate mutants (single, open triangle; double, horizontal hexagon; 3-point, pentagon; 4-point, square; 5-point, diamond; and 6-point, closed triangle) for the first conversion (from β-HCH to PCHL: X axis) and the second conversion (from PCHL to TCDL: Y axis) steps (Table 1) were plotted in logarithmical values. The effects of A112V (b), I138L (c), M253I (d), A81T (e), and A135T (f) mutations were extracted from the total plot (a) and shown by arrows. One potential evolutionary route from LinBUT to LinBMI by the accumulation of seven point mutations is shown by arrows (a).