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. 2021 Oct 18;22(20):11246. doi: 10.3390/ijms222011246

Figure 3.

Figure 3

DNA intercalation of AK-I-190. (A) Interaction of AK-I-190 with ct-DNA was monitored using UV/vis spectroscopy. UV/vis spectrum for ct-DNA (200 μM) in the presence of various AK-I-190 concentrations (0–200 μM) in 10 mM Tris buffer (pH 7.4). (B) Fluorescence spectra during titration of AK-I-190 to the complex of ct-DNA with EtBr (intercalator). The EtBr-DNA complex was excited at 471 nm and emission spectra were recorded from 500 nm to 700 nm. Fluorescence intensity decreased with subsequent addition of AK-I-190 (left) and m-AMSA (right). (C) KI quenching experiment. Stern–Volmer plot of fluorescence quenching of AK-I-190 (100 μM) by increasing KI concentration (0–9 mM) in 10 mM Tris buffer (pH 7.4) in the presence (red) and absence (black) of ct-DNA. (D,E) Molecular docking study of AK-I-190. Docking studies of AK-I-190 were carried out using the X-ray crystal structure of human DNA complexed with ellipticine as a template (PDB code, 1Z3F) using the Flare program. AK-I-190 potentially binds to DNA double helix by intercalation between base pairs. Each DNA strand is shown as blue and pink highlighted lines. Residues participating in the interaction are indicated by bold sticks and AK-I-190 is shown by capped sticks. Both are colored according to atom (carbon, black or green; oxygen, red; nitrogen, blue; phosphorus, cyan; fluoride, light green). Expected hydrogen bonds are indicated as green solid lines and π–π interactions are represented as purple solid lines. (F) Two-dimensional diagram of the interaction between AK-I-190 and the DNA double helical structure. The diagram was created using Pose View in proteins.plus/ (accessed on 20 August 2021).