Comprehensive views toward the biomolecular recognition of an anticancer drug, leflunomide with human serum albumin

Biomolecular association of an anticancer drug, leflunomide (LEF) with human serum albumin (HSA), the leading ligands carrier in human circulation was characterized using biophysical (i.e., fluorescence, absorption and voltammetric) methods and computational (i.e., molecular docking and molecular dynamics simulation) techniques. Evaluations of fluorescence, absorption and voltammetric findings endorsed the complex formation between LEF and HSA. An inverse relationship of Stern-Volmer constant-temperature and hyperchromic shift of the protein's absorption signal with addition of LEF con-firmed the LEF quenched the HSA fluorescence through static process. Moderate nature of binding strength (binding constant = 2.76-4.77 x 10(4) M-1) was detected towards the LEF-HSA complexation, while the association process was naturally driven via hydrophobic interactions, van der Waals interactions and hydrogen bonds, as evident from changes in entropy (?S= + 19.91 J mol K--1(-1)) and enthalpy (?H = -20.09 kJ mol (-1)), and molecular docking assessments. Spectral analyses of synchron-ous and three-dimensional fluorescence validated microenvironmental fluctuations near Trp and Tyr residues upon LEF binding to the protein. LEF association with HSA significantly defended tempera-ture-induced destabilization of the protein. Although LEF was found to attach to HSA at Sudlow's sites I and II, but exhibited greater preference toward its site I, as detected by the investigations of com-petitive site-marker displacement. Molecular dynamics simulation assessment revealed that the com-plex attained equilibrium throughout simulations, showing the LEF-HSA complex constancy.

Automated summary

The biomolecular association between the anticancer drug leflunomide (LEF) and human serum albumin (HSA) was characterized using biophysical and computational methods. The results confirmed the complex formation between LEF and HSA through fluorescence, absorption, and voltammetric findings. The binding process was driven by hydrophobic interactions, van der Waals interactions, and hydrogen bonds. Spectral analysis validated microenvironmental fluctuations near Trp and Tyr residues upon LEF binding to the protein. Molecular dynamics simulation revealed the stability of the LEF-HSA complex throughout the simulations.