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Comparative Study of Flavins Binding with Human Serum Albumin: A Fluorometric, Thermodynamic, and Molecular Dynamics Approach
Author(s) -
Sengupta Abhigyan,
Sasikala Wilbee D.,
Mukherjee Arnab,
Hazra Partha
Publication year - 2012
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201200044
Subject(s) - flavin group , chemistry , isothermal titration calorimetry , flavin mononucleotide , flavin adenine dinucleotide , human serum albumin , flavoprotein , binding constant , binding site , stereochemistry , biochemistry , cofactor , enzyme
Flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) are derivatives of riboflavin (RF), a water‐soluble vitamin, more commonly known as vitamin B 2 . Flavins have attracted special attention in the last few years because of the recent discovery of a large number of flavoproteins. In this work, these flavins are used as extrinsic fluorescence markers for probing the microheterogeneous environment of a well‐known transport protein, human serum albumin (HSA). Steady‐state and time‐resolved fluorescence experiments confirm that both FMN and FAD bind to the Sudlow’s site‐1 (SS1) binding pocket of HSA, where Trp214 resides. In the case of RF, a fraction of RF molecules binds at the SS1, whereas the major fraction of RF molecules remains unbound or surface bound to the protein. Moreover, flavin(s)–HSA interactions are monitored with the help of isothermal titration calorimetry, which provides free energy, enthalpy, and entropy changes of binding along with the binding constants. The molecular picture of binding interaction between flavins and HSA is well explored by docking and molecular dynamics studies.