title: Methyl-triclosan binding to human serum albumin: multi-spectroscopic study and visualized molecular simulation.
abstract: Methyl-triclosan (MTCS), a transformation product and metabolite of triclosan, has been widely spread in environment through the daily use of triclosan which is a commonly used anti-bacterial and anti-fungal substance in consumer products. Once entering human body, MTCS could affect the conformation of human serum albumin (HSA) by forming MTCS-HSA complex and alter function of protein and endocrine in human body. To evaluate the potential toxicity of MTCS, the binding mechanism of HSA with MTCS was investigated by UV-vis absorption, circular dichroism and Fourier transform infrared spectroscopy. Binding constants, thermodynamic parameters, the binding forces and the specific binding site were studied in detail. Binding constant at room tempreture (T = 298K) is 6.32 × 10(3)L mol(-1); ΔH(0), ΔS(0) and ΔG(0) were 22.48 kJ mol(-1), 148.16 J mol(-1)K(-1) and -21.68 kJ mol(-1), respectively. The results showed that the interactions between MTCS and HSA are mainly hydrophobic forces. The effects of MTCS on HSA conformation were also discussed. The binding distance (r = 1.2 nm) for MTCS-HSA system was calculated by the efficiency of fluorescence resonance energy transfer. The visualized binding details were also exhibited by molecular modeling method and the results could agree well with that from the experimental study.
authors.affiliation: Department of Chemistry, Lanzhou University, Lanzhou 730000, China; Interdisciplinary Nanotoxicity Center, Department of Chemistry, Jackson State University, Jackson, MS 39217, United States. Electronic address: lvwenj@lzu.edu.cn.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Lv
authors.forename: Yonglei
authors.initials: Y
authors.lastname: Chen
authors.forename: Dayong
authors.initials: D
authors.lastname: Li
authors.forename: Xingguo
authors.initials: X
authors.lastname: Chen
authors.forename: Jerzy
authors.initials: J
authors.lastname: Leszczynski
mesh_terms: D001665:Binding Sites; D002942:Circular Dichroism; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D008968:Molecular Conformation; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014260:Triclosan / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D012709:Serum Albumin; D014260:Triclosan; C502486:methyl triclosan
keywords: Human serum albumin; Methyl-triclosan; Molecular modeling; Spectroscopic techniques