title: Kaempferol-human serum albumin interaction: characterization of the induced chirality upon binding by experimental circular dichroism and TDDFT calculations.
abstract: The experimental induced circular dichroism (ICD) and absorption spectra of the achiral flavonoid kaempferol upon binding to human serum albumin (HSA) were correlated to electronic CD and UV-vis spectra theoretically predicted by time-dependent density functional theory (TDDFT). The neutral and four anionic species of kaempferol in various conformations were considered in the calculations. The appearance of the experimental ICD signal was rationalized in terms of kaempferol binding to HSA in a distorted, chiral, rigid conformation. The comparison between the experimental and simulated spectra allowed for the identification of the kaempferol species that binds to HSA, namely the anion generated by deprotonation of the hydroxyl group in position 7. This approach constitutes a convenient method for evidencing the binding species and for determining its conformation in the binding pocket of the protein. Its main advantage over the UV-vis absorption method lays in the fact that only the bound ligand species gives an ICD signal.
authors.affiliation: Department of Physical Chemistry, University of Bucharest, Bd. Regina Elisabeta 4-12, 030018 Bucharest, Romania.
authors.forename: Iulia
authors.initials: I
authors.lastname: Matei
authors.forename: Sorana
authors.initials: S
authors.lastname: Ionescu
authors.forename: Mihaela
authors.initials: M
authors.lastname: Hillebrand
mesh_terms: D000042:Absorption; D002942:Circular Dichroism; D004583:Electrons; D006801:Humans; D044949:Kaempferols / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008968:Molecular Conformation; D062105:Molecular Docking Simulation; D011789:Quantum Theory; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism*; D013816:Thermodynamics; D013997:Time Factors
chemical_list: D044949:Kaempferols; D012709:Serum Albumin; C006552:kaempferol