Figure 5. Relative interaction energy in kcal/mol between CPT/hCPT-derivatives and the Top1/dsDNA active-site.

The interaction energy scores for the derivatives of CPT and hCPT were subtracted from the score of the respective parent inhibitor with the resulting difference values plotted on the graph. The CPT and hCPT interaction energy scores were set to zero. A negative kcal/mol score indicates that a derivative bound tighter than the parent inhibitor, while a positive kcal/mol score indicates that it bound weaker than the parent inhibitor. A) Interaction energy values for CPT, hCPT and derivatives when bound in the Rotated +1 Nucleoside model Top1/dsDNA active-site. B) Interaction energy values for CPT, hCPT and derivatives bound in the Intercalated model Top1/dsDNA active-site.