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Interaction of (−)‐epigallocatechin‐3‐gallate with human serum albumin: Fluorescence, fourier transform infrared, circular dichroism, and docking studies
Author(s) -
Maiti Tushar Kanti,
Ghosh Kalyan Sundar,
Dasgupta Swagata
Publication year - 2006
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.20995
Subject(s) - chemistry , circular dichroism , hydrogen bond , van der waals force , fourier transform infrared spectroscopy , human serum albumin , epigallocatechin gallate , protein secondary structure , hydrophobic effect , docking (animal) , fluorescence , quenching (fluorescence) , enthalpy , crystallography , analytical chemistry (journal) , stereochemistry , photochemistry , molecule , chromatography , organic chemistry , biochemistry , antioxidant , polyphenol , medicine , physics , nursing , quantum mechanics
(−)‐Epigallocatechin‐3‐gallate (EGCG), the major constituent of green tea has been reported to prevent many diseases by virtue of its antioxidant properties. The binding of EGCG with human serum albumin (HSA) has been investigated for the first time by using fluorescence, circular dichroism (CD), Fourier transform infrared (FTIR) spectroscopy, and protein‐ligand docking. We observed a quenching of fluorescence of HSA in the presence of EGCG. The binding parameters were determined by a Scatchard plot and the results were found to be consistent with those obtained from a modified Stern‐Volmer equation. From the thermodynamic parameters calculated according to the van't Hoff equation, the enthalpy change Δ H ° and entropy change Δ S ° were found to be −22.59 and 16.23 J/mol K, respectively. These values suggest that apart from an initial hydrophobic association, the complex is held together by van der Waals interactions and hydrogen bonding. Data obtained by fluorescence spectroscopy, CD, and FTIR experiments along with the docking studies suggest that EGCG binds to residues located in subdomains IIa and IIIa of HSA. Specific interactions are observed with residues Trp 214, Arg 218, Gln 221, Asn 295 and Asp 451. We have also looked at changes in the accessible surface area of the interacting residues on binding EGCG for a better understanding of the interaction. Proteins 2006. © 2006 Wiley‐Liss, Inc.