Research Paper Volume 14, Issue 2 pp 678—707

Figure 3. KB1541 interacts with 14–3–3ζ protein. (A) Binding mode of the KB1541 in ATP synthase 5 alpha (PDB ID: 2JDI). Dotted lines indicate hydrogen bonding interactions. Docking studies exhibited the possible hydrogen bonding interactions of KB1541 with S177 and Q430 in ATP synthase 5 alpha at 3.00 and 2.15 Å, respectively. (B) Binding mode of the KB1541 in ATP synthase 5 beta (PDB ID: 2JDI). Dotted lines indicate hydrogen bonding interactions. Docking studies exhibited three possible hydrogen bonding interactions of KB1541 with ATP synthase 5 beta (2.91, 3.28 and 3.35 Å). (C) Binding mode of the KB1541 in 14–3–3ζ. (PDB ID: 6FN9). Dotted lines indicate hydrogen bonding interactions. Docking studies of KB1541 with 14–3–3ζ showed that the best-docked pose was surrounded by K49, R56 and Y128. KB1541 was predicted to make strong hydrogen bonds with 14–3–3ζ using the central oxazoloquinoline ring (2.12, 2.97, 3.12 and 2.37 Å). (D) Microscale thermophoresis (MST) assay to quantify the binding between KB1541 and 14–3–3ζ protein. Data obtained was plotted with concentration on X-axis and Fnorm on Y-axis to find out the dissociation constant (K_d). Fnorm value is calculated by dividing F₁ by F₀. F₁ is the fluorescence value measured in the heated state, and F₀ corresponds to the fluorescence value measured in the cold state before turning on the IR laser. K_d was found to be 29.8 μM, confirming a tight interaction between KB1541 and 14–3–3ζ protein.