Department of Physics, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand 826004, India.
Department of Chemistry, National Institute of Technology, Rourkela, Odisha 769008, India.
Food Chem. 2020 May 15;312:126064. doi: 10.1016/j.foodchem.2019.126064. Epub 2019 Dec 19.
Biophysical insight into the binding interaction between the major whey protein, β-Lactoglobulin (βLG) and vitamin B12, was studied using different spectroscopic tools such as steady-state & time-resolved fluorescence spectroscopy, Circular Dichroism (CD) and Fluorescence Correlation Spectroscopy (FCS). The intrinsic fluorescence of βLG was quenched by vitamin B12. From the time-resolved fluorescence experiment, the nature of quenching was found to be static suggesting ground-state complex formation between βLG and vitamin B12, which was also supported by the excitation spectra. Synchronous fluorescence spectra revealed that the tryptophan residue microenvironment of βLG was affected by the vitamin B12. The CD spectra suggested that the secondary structure of the βLG remains unaffected by vitamin B12. From the FCS experiment, the tertiary structure of βLG was observed to be stable in the presence of vitamin B12 at the single-molecule level. The outcome of this study might have potential applications in the food and pharmaceutical industry.
本研究使用多种光谱技术，如稳态和时间分辨荧光光谱、圆二色性（CD）和荧光相关光谱（FCS），深入研究了主要乳清蛋白β-乳球蛋白（βLG）与维生素 B12 之间的结合相互作用。维生素 B12 猝灭了βLG 的固有荧光。从时间分辨荧光实验可知，猝灭为静态猝灭，表明βLG 与维生素 B12 之间形成了基态复合物，这也得到了激发光谱的支持。同步荧光光谱表明，维生素 B12 影响了βLG 中色氨酸残基微环境。CD 光谱表明，βLG 的二级结构不受维生素 B12 的影响。从 FCS 实验中可以看出，在单分子水平上，βLG 的三级结构在存在维生素 B12 的情况下保持稳定。这项研究的结果可能在食品和制药行业有潜在的应用。
