Spectroscopic analysis on the binding interaction between tetracycline hydrochloride and bovine proteins β-casein, α-lactalbumin

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• 作者：Hongna Bi ; Lin Tang ; ^{tanglin@sdnu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Xin Gao ; Jingjing Jia ; Henghui Lv
• 关键词：TCH ; Tetracycline hydrochloride ; β-CN ; β-casein ; α-LA ; α-Lactalbumin ; PBS ; Phosphate buffer solution ; ANS ; 8-Anilino-1-naphthalenesulfonic acid ; UV&ndash ; vis absorption spectra ; Ultraviolet visible absorption spectra ; EEM ; Excitation-Emission Matrix ; CD spectra ; Circular dichroism spectra ; FRET ; Fluorescence resonance energy transfer
• 刊名：Journal of Luminescence
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：178
• 期：Complete
• 页码：72-83
• 全文大小：5622 K

文摘

We investigated the binding interaction between tetracycline hydrochloride (TCH) and bovine proteins β-casein (β-CN), α-lactalbumin (α-LA) in aqueous solution by multi-spectroscopic methods and molecular modeling techniques. Fluorescence and time-resolved fluorescence showed that TCH effectively quenched the intrinsic fluorescence of bovine proteins via static quenching, while there was a single class of binding site on protein. Thermodynamic parameters revealed that electrostatic forces played major roles in the interaction between β-CN and TCH, whereas α-LA-TCH complex were stabilized by hydrogen bonds and van der Waals forces. Moreover, circular dichroism　spectra (CD spectra), ultraviolet visible absorption spectra (UV–vis absorption spectra), and fluorescence Excitation-Emission Matrix (EEM) spectra results indicated the secondary structure of bovine proteins was changed in the presence of TCH with the α-helix percentage of protein-TCH complexes decreased. Molecular modeling analysis supported the experimental results well. In addition, the research of surface hydrophobicity further verified tertiary structure of proteins was changed in the presence of TCH and the possible changes of protein function. These results achieved from experiments may be valuable in the milk industry and food safety.