title: Probing the interaction of a therapeutic flavonoid, pinostrobin with human serum albumin: multiple spectroscopic and molecular modeling investigations.
abstract: Interaction of a pharmacologically important flavonoid, pinostrobin (PS) with the major transport protein of human blood circulation, human serum albumin (HSA) has been examined using a multitude of spectroscopic techniques and molecular docking studies. Analysis of the fluorescence quenching data showed a moderate binding affinity (1.03 × 10(5) M(-1) at 25°C) between PS and HSA with a 1∶1 stoichiometry. Thermodynamic analysis of the binding data (ΔS = +44.06 J mol(-1) K(-1) and ΔH = -15.48 kJ mol(-1)) and molecular simulation results suggested the involvement of hydrophobic and van der Waals forces, as well as hydrogen bonding in the complex formation. Both secondary and tertiary structural perturbations in HSA were observed upon PS binding, as revealed by intrinsic, synchronous, and three-dimensional fluorescence results. Far-UV circular dichroism data revealed increased thermal stability of the protein upon complexation with PS. Competitive drug displacement results suggested the binding site of PS on HSA as Sudlow's site I, located at subdomain IIA, and was well supported by the molecular modelling data.
authors.affiliation: Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Shevin R
authors.initials: SR
authors.lastname: Feroz
authors.forename: Saharuddin B
authors.initials: SB
authors.lastname: Mohamad
authors.forename: Zarith S D
authors.initials: ZS
authors.lastname: Bakri
authors.forename: Sri N A
authors.initials: SN
authors.lastname: Malek
authors.forename: Saad
authors.initials: S
authors.lastname: Tayyab
mesh_terms: D002942:Circular Dichroism; D044950:Flavanones / Q000493:pharmacokinetics*; D006801:Humans; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D011485:Protein Binding; D011487:Protein Conformation; D012709:Serum Albumin / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D044950:Flavanones; D012709:Serum Albumin; C411294:pinostrobin