title: Biointeractions of C.I. Acid Red 2 and its structural analogues with transporter albumin: Fluorescence, circular dichroism, and ligand docking approaches.
abstract: In this contribution, the toxicological effects of C.I. Acid Red 2 and 1-(2-pyridylazo)-2-naphthol (PAN) have been elucidated by utilizing plasma albumin as a biological model. Fluorescence data indicated that the Trp-214 residue was quenched by both azo compounds, but the quenching degree of C.I. Acid Red 2 is less than PAN. According to the results of time-resolved fluorescence decay, it may be observed that the quenching of Trp-214 residue is controlled by static type; this corroborates the Stern-Volmer analyses and the conformational transition of protein was concurred. The experiments also found that azo colorants are situated within subdomain IIA, several amino acid residues, such as Ser-202, Ala-210, and Trp-214 were believed to be yielded direct interaction with the two chemicals, yet the operating distances between C.I. Acid Red 2 and relevant residues are greater than PAN. Interestingly, we may ascertain that the azo colorants with naphthalene ring possess stronger affinity with protein than those just having benzene ring in their molecular structure. This suggested that the existence of naphthalene ring substituent could hold relatively great risk for the human body due to large hydrophobicity (cLogP); therefore, the hydrophobicity of azo colorants can probably be a major element of its toxicological activities.
authors.affiliation: College of Agriculture and Plant Protection, Qingdao Agricultural University, Qingdao 266109, China; College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China; Department of Chemistry, China Agricultural University, Beijing 100193, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Peng
authors.affiliation: College of Agriculture and Plant Protection, Qingdao Agricultural University, Qingdao 266109, China; Department of Chemistry, China Agricultural University, Beijing 100193, China; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States. Electronic address: alexf.ting@outlook.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Ding
authors.affiliation: State Key Laboratory of the Discovery and Development of Novel Pesticide, Shenyang Research Institute of Chemical Industry Co. Ltd., Shenyang 110021, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Xie
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D001665:Binding Sites; D002942:Circular Dichroism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008024:Ligands; D062105:Molecular Docking Simulation; D009284:Naphthols / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D014443:Tyrosine / Q000737:chemistry
chemical_list: D001391:Azo Compounds; D008024:Ligands; D009284:Naphthols; D012709:Serum Albumin; C041728:1-(2-pyridylazo)-2-naphthol; D014443:Tyrosine; C008492:methyl red
keywords: Azo colorant; Hydrophobicity; Ligand docking; Plasma albumin; Spectrometry; Structure-activity relationships