Synthesis and binding with BSA of a new gemini surfactant

We have synthesized a new gemini surfactant, glycol bis-N-tetradecyl nicotinate dibromide (designed as P14-1-14), and probed its combination with bovine serum albumin (BSA) by fluorescence spectroscopy, dual polarization interferometry (DPI), proton nuclear magnetic resonance spectroscopy (1H NMR), Fourier transform infrared spectroscopy (FTIR) and molecular docking. The experiments revealed, in one hand, P14-1-14 quenched the intrinsic fluorescence of BSA by way of forming BSA/P14-1-14 complex with a binding constant of 2.14 × 104 L mol−1 at 293 K, that P14-1-14 augmented the thickness, mass, the refractive index (RI) and density of BSA, and that P14-1-14 declined the contents of α-helix (from 54.01% to 29.41%) but raised the random structure (from 7.86% to 22.27%). On the other hand, BSA shifted the proton resonance signals of P14-1-14 up-field and reduced relaxation time. The molecular docking manifested P14-1-14 embedded into subdomain of BSA, which made possible the π–π stacking between the electron-deficit pyridinium rings in P14-1-14 and the electron-abundant pyrrole ring in Trp residues of BSA, and that hydrogen bonding and hydrophobic interaction also took place during the binding. Therefore, the present work offers a whole view of the interaction of BSA with a new gemini surfactant.