Kinetic and Thermodynamic Study of Margatoxin Peptide Interaction with Human Serum Albumin: Studied by Biophysical and Docking Methods

The scorpion-derived peptide margatoxin (MgTx) can make it possible to create novel and targeted medications for treatment of cancer. In this study, for the first time, we report an investigation of the human serum albumin (HSA) protein interaction with MgTx in aqueous solution. For this, biophysical methods including spectral, surface plasmon resonance (SPR), zeta potential and also in silico molecular docking technique at physiological conditions were used for examining kinetic binding and thermodynamic data. This interaction was done for a series of MgTx concentrations at three temperatures. The comparison of the K_D kinetic value at 308 ° K and 298 ° K in SPR and UV spectroscopy shows that the complex between the MgTx and HSA has high strength at lower temperatures. The resulted positive data for ΔH and ΔS show that the major interaction force involved in the formation of the MgTx/HSA complex is hydrophobic forces. Also, the decreasing of zeta-potential values by adding of MgTx concentrations confims that the MgTx molecules could bind to HSA more by hydrophobic forces. In addition, according to the docking results, there are a very small number of strong interactions such as hydrogen bonds and salt bridges compared to the hydrophobic forces in the HSA and MgTx interaction.

Graphical Abstract