title: Studies on the interaction between vincamine and human serum albumin: a spectroscopic approach.
abstract: The interaction between vincamine (VCM) and human serum albumin (HSA) has been studied using a fluorescence quenching technique in combination with UV/vis absorption spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD) spectroscopy and molecular modeling under conditions similar to human physiological conditions. VCM effectively quenched the intrinsic fluorescence of HSA via static quenching. The binding constants were calculated from the fluorescence data. Thermodynamic analysis by Van't Hoff equation revealed enthalpy change (ΔH) and entropy change (ΔS) were -4.57 kJ/mol and 76.26 J/mol/K, respectively, which indicated that the binding process was spontaneous and the hydrophobic interaction was the predominant force. The distance r between the donor (HSA) and acceptor (VCM) was obtained according to the Förster's theory of non-radiative energy transfer and found to be 4.41 nm. Metal ions, viz., Na(+), K(+), Li(+), Ni(2+), Ca(2+), Zn(2+) and Al(3+) were found to influence binding of the drug to protein. The 3D fluorescence, FT-IR and CD spectral results revealed changes in the secondary structure of the protein upon interaction with VCM. Furthermore, molecular modeling indicated that VCM could bind to the subdomain IIA (site I) of HSA.
authors.affiliation: Department of Cell Biology, College of Life Science and Technology, Jinan University, Guangzhou, People's Republic of China.
authors.forename: Hanlin
authors.initials: H
authors.lastname: Pu
authors.forename: Hua
authors.initials: H
authors.lastname: Jiang
authors.forename: Rongrong
authors.initials: R
authors.lastname: Chen
authors.forename: Hongcui
authors.initials: H
authors.lastname: Wang
mesh_terms: D001665:Binding Sites; D005453:Fluorescence; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods*; D013816:Thermodynamics; D014749:Vincamine / Q000737:chemistry*
chemical_list: D012709:Serum Albumin; D014749:Vincamine
keywords: circular dichroism (CD); fluorescence quenching; human serum albumin; molecular modeling; vincamine