Deciphering the binding mode and structural perturbations in floxuridine-human serum albumin complexation with spectroscopic, microscopic, and computational techniques
Document Type
Article
Publication Date
3-5-2024
Abstract
The binding mode of antineoplastic antimetabolite, floxuridine (FUDR), with human serum albumin (HSA), the leading carrier in blood circulation, was ascertained using multi-spectroscopic, microscopic, and computational techniques. A static fluorescence quenching was established due to decreased Ksv values with rising temperatures, suggesting FUDR-HSA complexation. UV-vis absorption spectral results also supported this conclusion. The binding constant, Ka values, were found within 9.7-7.9 x 103 M-1 at 290, 300, and 310 K, demonstrating a moderate binding affinity for the FUDR-HSA system. Thermodynamic data (Delta S = +46.35 J.mol-1.K-1 and Delta H =-8.77 kJ.mol-1) predicted the nature of stabilizing forces (hydrogen-bonds, hydrophobic, and van der Waals interactions) for the FUDR-HSA complex. Circular dichroism spectra displayed a minor disruption in the pro-tein's 2 degrees and 3 degrees structures. At the same time, atomic force microscopy images proved variations in the FUDR-HSA surface morphology, confirming its complex formation. The protein's microenvironment around Trp/Tyr resi-dues was also modified, as judged by 3-D fluorescence spectra. FUDR-bound HSA showed better resistance against thermal stress. As disclosed from ligand displacement studies, the FUDR binding site was placed in subdomain IIA (Site I). Further, the molecular docking analysis corroborated the competing displacement studies. Molecular dynamics evaluations revealed that the complex achieved equilibrium during simulations, confirming the FUDR-HSA complex's stability.
Keywords
Floxuridine, Human serum albumin, Fluorescence spectroscopy, Atomic force microscopy, Molecular dynamic simulations
Divisions
oralcraniofacial,InstituteofBiologicalSciences
Funders
Higher Education Commission of Pakistan
Publication Title
Spectrochimica Acta Part A-Molecular and Biomolecular Spectroscopy
Volume
308
Publisher
Pergamon-Elsevier Science Ltd
Publisher Location
THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND