Spectroscopic study on the interaction between mononaphthalimide spermidine (MINS) and bovine serum albumin (BSA)

• Polyamine-conjugate caused the conformational alteration of BSA.
• MINS bound to BSA.
• By and large, the fluorescent quenching mechanism was a static type.
• The type of interaction force was mainly hydrophobic.
• Docking model for compound 1 with BSA was also investigated.

The interaction mononaphthalimide spermidine (MINS, 1) and bovine serum albumin (BSA) was studied by UV/vis absorption, fluorescence and circular dichroism spectra (CD) under physiological conditions (pH = 7.4). The observed spectral quenching of BSA by compound 1 indicated compound 1 could bind to BSA. Further fluorescent tests revealed that the quenching mechanism of BSA by compound 1 was overall static. Meanwhile, the obtained binding constant and thermodynamic parameters on compound-BSA interaction showed that the type of interaction force of compound 1 and BSA was mainly hydrophobic. The analysis of synchronous, three-dimensional fluorescence and CD showed that compound 1 had weak influence on the conformational changes in BSA. Molecular docking simulation was performed and docking model in silico suggested that the configuration of compound 1 was localized in enzymatic drug site II in BSA. Furthermore, naphthalimide moiety of compound 1 greatly contributed to the hydrophobic interaction between compound 1 and BSA protein, as confirmed by experimental data.

The interaction between mononaphthalimide spermidine (MINS) with bovine serum albumin (BSA) was studied by UV/vis absorption, fluorescent and dichroism spectra (CD) under physiological conditions. Docking model for compound 1 with BSA was also investigated.Figure optionsDownload as PowerPoint slide