title: Interaction mechanisms between organic UV filters and bovine serum albumin as determined by comprehensive spectroscopy exploration and molecular docking.
abstract: Organic UV filters are a group of emerging PPCP (pharmaceuticals and personal care products) contaminants. Current information is insufficient to understand the in vivo processes and health risks of organic UV filters in humans. The interaction mechanism of UV filters with serum albumin provides critical information for the health risk assessment of these active ingredients in sunscreen products. This study investigates the interaction mechanisms of five commonly used UV filters (2-hydroxy-4-methoxybenzophenone, BP-3; 2-ethylhexyl 4-methoxycinnamate, EHMC; 4-methylbenzylidene camphor, 4-MBC; methoxydibenzoylmethane, BDM; homosalate, HMS) with bovine serum albumin (BSA) by spectroscopic measurements of fluorescence, circular dichroism (CD), competitive binding experiments and molecular docking. Our results indicated that the fluorescence of BSA was quenched by these UV filters through a static quenching mechanism. The values of the binding constant (Ka) ranged from (0.78±0.02)×10(3) to (1.29±0.01)×10(5) L mol(-1). Further exploration by synchronous fluorescence and CD showed that the conformation of BSA was demonstrably changed in the presence of these organic UV filters. It was confirmed that the UV filters can disrupt the α-helical stability of BSA. Moreover, the results of molecular docking revealed that the UV filter molecule is located in site II (sub-domain IIIA) of BSA, which was further confirmed by the results of competitive binding experiments. In addition, binding occurred mainly through hydrogen bonding and hydrophobic interaction. This study raises critical concerns regarding the transportation, distribution and toxicity effects of organic UV filters in human body.
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Ao
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; School of Resource and Environment, Ningxia University, Yinchuan 750021, China.
authors.forename: Li
authors.initials: L
authors.lastname: Gao
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: taoyuan@sjtu.edu.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Yuan
authors.affiliation: School of Public Health, Medical College, Wuhan University of Science and Technology, Wuhan, Hubei 430065, China.
authors.forename: Gaofeng
authors.initials: G
authors.lastname: Jiang
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D002942:Circular Dichroism; D006801:Humans; D006860:Hydrogen Bonding; D062105:Molecular Docking Simulation; D011485:Protein Binding; D011487:Protein Conformation; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013473:Sunscreening Agents / Q000737:chemistry / Q000633:toxicity*; D013816:Thermodynamics
chemical_list: D013473:Sunscreening Agents; D012710:Serum Albumin, Bovine
keywords: Bovine serum albumin; Interaction mechanisms; Molecular docking; Organic UV filters; Spectroscopy