Fig. 3
From: Tetrahydropyrido[4,3-d]pyrimidines as a new active scaffold for human topoisomerase II inhibitors

Binding modes from docking calculations for ARN21929 at the DNA cleavage and ATP sites of TopoII. (A) Binding pose of ARN21929 within the DNA-cleaved complex. (B) Binding pose of ARN21929 within the ATP-binding site in the presence of Mg²⁺. (C) Binding pose of ARN21929 within the ATP-binding site in the absence of Mg²⁺. The protein and DNA (present only in A) are shown in semi-transparent cartoon representation, while the nucleotide bases and ligand are displayed in licorice representation. Residues involved in van der Waals interactions are shown in semi-transparent licorice representation. Details on the interactions of each compound in the pockets are reported in the main text.