In WT, the secondary structure content of loop-region are primarily the mixture of turns Å which is larger than the 10 Å in WT (Fig. ). The secondary structure change in the R539T is similar to the WT. In C580y, the secondary structure consists of turns and α-helix from 0 to 83 ns, afterwards, it is dominated by turns and a mixture of α-helix and 3 10 -helix. Comparison of the average distance between the loop-region, we obtained the value of 11.94, 14.18 and 23.08 Å for the R539T, I543T and C580Y mutants respectively.