title: Spectroscopy and molecular docking study on the interaction of daidzein and genistein with pepsin.
abstract: The interaction of pepsin with daidzein (Dai) or genistein (Gen) was investigated using spectroscopic techniques under simulated physiological conditions. Dai and Gen can quench the fluorescence of pepsin and the quenching mechanism was a static process. The binding site number n and apparent binding constant K were measured at different temperatures. The thermodynamic parameters ΔΗ, ΔG and ΔS were calculated. The results indicated that van der Waals forces and hydrogen bond formation played major roles in the interaction of Dai or Gen with pepsin. The binding distance between pepsin and Dai or Gen was calculated according to energy transfer theory. The results of synchronous fluorescence spectra showed that the microenvironment and conformation of pepsin were changed. UV absorption and 3D fluorescence spectra showed that the binding interaction disturbed the microenvironment of amino acid residues and induced conformational changes in pepsin. Molecular docking results showed that Dai and Gen entered into the hydrophobic cavity of pepsin and two hydrogen bonds formed between Dai or Gen and pepsin. The results demonstrated that the interaction behavior between Dai and Gen with pepsin was slightly different, which denoted that the 5-hydroxyl group of Gen, to a certain extent, had an effect on ligand binding to proteins. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: School of Pharmacy, Xi'an Jiaotong University, Shaanxi, 710061, People's Republic of China.
authors.forename: Guanjun
authors.initials: G
authors.lastname: Nan
authors.affiliation: Department of Obstetrics and Gynecology, Xi'an No.4 Hospital, Shaanxi, 710004, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: School of Pharmacy, Xi'an Jiaotong University, Shaanxi, 710061, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.affiliation: School of Pharmacy, Xi'an Jiaotong University, Shaanxi, 710061, People's Republic of China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Lv
authors.affiliation: School of Pharmacy, Xi'an Jiaotong University, Shaanxi, 710061, People's Republic of China.
authors.forename: Meiwen
authors.initials: M
authors.lastname: Ding
authors.affiliation: School of Pharmacy, Xi'an Jiaotong University, Shaanxi, 710061, People's Republic of China.
authors.forename: Liu
authors.initials: L
authors.lastname: Yang
authors.affiliation: School of Pharmacy, Xi'an Jiaotong University, Shaanxi, 710061, People's Republic of China.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Pharmacy, Xi'an Jiaotong University, Shaanxi, 710061, People's Republic of China.
authors.forename: Guangde
authors.initials: G
authors.lastname: Yang
mesh_terms: D019833:Genistein / Q000737:chemistry*; D006860:Hydrogen Bonding; D007529:Isoflavones / Q000737:chemistry*; D008968:Molecular Conformation; D062105:Molecular Docking Simulation; D010434:Pepsin A / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D007529:Isoflavones; C004742:daidzein; D019833:Genistein; D010434:Pepsin A
keywords: daidzein; fluorescence quenching; genistein; molecular docking; pepsin