Probing the interaction of 2,4-dichlorophenoxyacetic acid with human serum albumin as studied by experimental and computational approaches
Document Type
Article
Publication Date
1-1-2019
Abstract
To characterize the binding of a widely used herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D) to the major transporter in human circulation, human serum albumin (HSA), multi-spectroscopic approaches such as fluorescence, absorption and circular dichroism along with computational methods were employed. Analysis of the fluorescence and absorption spectroscopic data confirmed the 2,4-D–HSA complex formation. A static quenching mechanism was evident from the inverse temperature dependence of the KSV values. The complex was stabilized by a weak binding affinity (Ka = 5.08 × 103 M−1 at 298 K). Quantitative analysis of thermodynamic data revealed participation of hydrophobic and van der Waals interactions as well as hydrogen bonds in the binding process. Circular dichroism and three-dimensional fluorescence spectral results showed structural (secondary and tertiary) changes in HSA as well as microenvironmental perturbation around protein fluorophores (Trp and Tyr residues) upon 2,4-D binding. Addition of 2,4-D to HSA was found to improve protein's thermal stability. Competitive displacement results as well as computational analyses suggested preferred location of the 2,4-D binding site as Sudlow's site I (subdomain IIA) in HSA.
Keywords
2, 4-Dichlorophenoxyacetic acid, Human serum albumin, Herbicide–protein interaction, Fluorescence quenching, Computational analysis
Divisions
InstituteofBiologicalSciences
Funders
Ministry of Higher Education, Government of Malaysia and the University of Malaya: High Impact Research MoE Grant (grant number UM.C/625/1/HIR/MoE/SC/02)
Publication Title
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Volume
207
Publisher
Elsevier