Elucidation of the binding mechanism of coumarin derivatives with human serum albumin

• Published in: PloS one Vol. 8; no. 5; p. e63805
• Main Authors: Garg, Archit, Manidhar, Darla Mark, Gokara, Mahesh, Malleda, Chandramouli, Suresh Reddy, Cirandur, Subramanyam, Rajagopal
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 28.05.2013; Public Library of Science (PLoS)
• Subjects: Albumin; Anticoagulants; Arthritis; Asthma; Binding; Binding Sites; Biochemistry; Biology; Buffers; Cancer; Chemical compounds; Chemistry; Circular Dichroism; Coagulants; Coumarin; Derivatives; Dichroism; Drugs; Dynamic stability; Ethanol; Fatty acids; Fluorescence; Fluorescence spectroscopy; Free energy; Human serum albumin; Humans; Hydrogen; Hydrogen bonds; Hydrogen-Ion Concentration; Hydrophobicity; Hymecromone - chemistry; Hymecromone - metabolism; Kinetics; Life sciences; Ligands; Molecular docking; Molecular Docking Simulation; Molecular dynamics; NMR; Nuclear magnetic resonance; pH effects; Pharmacology; Physiology; Plant sciences; Protein Binding; Protein structure; Protein Structure, Secondary; Proteins; Quenching; Secondary structure; Serum albumin; Serum Albumin - chemistry; Serum Albumin - metabolism; Spectrometry, Fluorescence; Spectroscopy; Studies; Thermodynamics; Time Factors
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0063805

Coumarin is a benzopyrone which is widely used as an anti-coagulant, anti-oxidant, anti-cancer and also to cure arthritis, herpes, asthma and inflammation. Here, we studied the binding of synthesized coumarin derivatives with human serum albumin (HSA) at physiological pH 7.2 by using fluorescence spectroscopy, circular dichroism spectroscopy, molecular docking and molecular dynamics simulation studies. By addition of coumarin derivatives to HSA the maximum fluorescence intensity was reduced due to quenching of intrinsic fluorescence upon binding of coumarin derivatives to HSA. The binding constant and free energy were found to be 1.957±0.01×10(5) M(-1), -7.175 Kcal M(-1) for coumarin derivative (CD) enamide; 0.837±0.01×10(5) M(-1), -6.685 Kcal M(-1) for coumarin derivative (CD) enoate, and 0.606±0.01×10(5) M(-1), -6.49 Kcal M(-1) for coumarin derivative methylprop (CDM) enamide. The CD spectroscopy showed that the protein secondary structure was partially unfolded upon binding of coumarin derivatives. Further, the molecular docking studies showed that coumarin derivatives were binding to HSA at sub-domain IB with the hydrophobic interactions and also with hydrogen bond interactions. Additionally, the molecular dynamics simulations studies contributed in understanding the stability of protein-drug complex system in the aqueous solution and the conformational changes in HSA upon binding of coumarin derivatives. This study will provide insights into designing of the new inspired coumarin derivatives as therapeutic agents against many life threatening diseases.