Binding effects of antibiotic drug sulfamethazine on the serum albumins: Multi-spectroscopic and computation approach

Abstract

Over the past decades, bio-macromolecules-drug binding interaction studies have been of great interest with varied applications in drug modification and development. Such reports help us to recognize the molecular aspects of the bindings correlating with the structural phenomenon. The binding study of an antibiotic drug, Sulfamethazine (SMZ) with plasma proteins, Human Serum Albumin (HSA), and Bovine Serum Albumin (BSA) have been investigated using spectroscopic and computational techniques. The UV–Vis and fluorescence spectroscopic data indicate towards potential binding affinity of the drug to the proteins through the formation of stable ground state complexes. Binding constants obtained were in the order of 104 M − 1 for both the cases, the values were comparatively higher for HSA than BSA. Thermodynamic parameters were estimated from temperature-dependent fluorescence analyses; enthalpy driven, exothermic nature of the binding interactions along with the predominance of electrostatic and hydrophobic forces were established in both the cases. Synchronous fluorescence and FT-IR spectra revealed the conformational changes in the protein structure(s). Molecular docking and dynamic studies further supported the complex formation in accordance with the experimental report(s). Molecular docking denoted binding of the drug at pocket-I of the active site in proteins, while molecular dynamic simulation established the stability and compactness of the complex due to binding.

Keywords

• Protein-ligand interaction
• Spectroscopy
• Thermodynamics
• Molecular Docking
• Molecular Dynamics