Evidence of the Differences Between Human and Bovine Serum Albumin Through the Interaction with Coumarin-343: Experimental (ICD) and Theoretical Studies (DFT and Molecular Docking)

Author(s)

de Souza, Carmen Regina ; Yoguim, Mauricio Ikeda ; Pavan, Nathalia Mariana ; Morgon, Nelson Henrique ; Ximenes, Valdecir Farias ; de Souza, Aguinaldo Robinson

• Document type: Journal article
• Source: BIOPHYSICA; v. 5, n. 3, p. 16-pg., 2025-07-15.

Abstract

Coumarins are known for interacting with proteins and exhibiting diverse biological activities. This study investigates the interaction between coumarin-343 (C343) and human (HSA) and bovine (BSA) serum albumins. Fluorescence spectroscopy and theoretical simulations, including density functional theory (DFT) and molecular docking, were used to analyze the ligand-protein complex formation. The fluorescence quenching data revealed that C343 binds to both proteins, with binding constants of 2.1 x 105 mol<middle dot>L-1 (HSA) and 6.5 x 105 mol<middle dot>L-1 (BSA), following a 1:1 stoichiometry. Binding site markers identified drug site I (DS1), located in subdomain IIA, as the preferential binding region for both proteins. Computational results supported these findings, showing high affinity for DS1, with binding energies of -69.02 kcal<middle dot>mol-1 (HSA) and -67.22 kcal<middle dot>mol-1 (BSA). While complex formation was confirmed for both proteins, differences emerged in the induced circular dichroism (ICD) signals. HSA displayed a distinct ICD profile compared to BSA in both intensity and absorption maximum. Molecular Docking revealed that the C343 conformation differed between HSA and BSA, explaining the variation in ICD signals. These results highlight the importance of protein structure in modulating ligand interactions and spectral responses. (AU)

• FAPESP's process: 13/08293-7 - CCES - Center for Computational Engineering and Sciences
• Grantee: Munir Salomao Skaf
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 19/12294-5 - Theoretical calculations of electronic spectra (UV-Vis, fluorescence and circular dichroism) of molecules of pharmacological and applied interest
• Grantee: Nelson Henrique Morgon
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/18445-5 - Synthesis, studies and applications of fluorescent and circular dichroic probes for characterization of interactions with proteins, DNA and determination of enzymatic activity
• Grantee: Valdecir Farias Ximenes
• Support Opportunities: Regular Research Grants
• FAPESP's process: 24/00959-0 - Fluorescent and Dichroic Probes: Development of Bioanalytical Methodologies
• Grantee: Valdecir Farias Ximenes
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/12950-7 - 2018 MRS Fall Meetings & Exhibits
• Grantee: Aguinaldo Robinson de Souza
• Support Opportunities: Research Grants - Meeting - Abroad
• FAPESP's process: 20/05535-3 - Computer simulation of the interaction between the antibiotic linezolid and the active site of the 50s ribosomal subunit of the bacterium Haloarcula marismortui
• Grantee: Giulia Saneti Grandini
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 15/22338-9 - Study of the interaction between drugs and human serum albumin (HSA) based on computer simulation, DFT and TDDFT, experiments of electronic circular dichroism, ECD, and determination of the bond formation constant
• Grantee: Aguinaldo Robinson de Souza
• Support Opportunities: Regular Research Grants