Sri Aurobindo Vidyamandir, Hoogly, Chandannagar, West Bengal, India.
The Department of Chemistry, The Bhawanipur Education Society College, Kolkata, 700020, West Bengal, India.
J Biol Inorg Chem. 2018 Aug;23(6):917-927. doi: 10.1007/s00775-018-1591-3. Epub 2018 Jul 13.
A ternary system comprising of a Eu(III) complex of the drug Tetracycline hydrochloride (EuTC) bound to bovine β-lactoglobulin variant A (BLGA) in aqueous buffer at physiological pH (pH = 7.4) has been investigated to exploit the enhanced "antenna effect" to locate the bound drug and find the microenvironment of the binding site. Steady-state and time-resolved emission studies at room temperature as well as at 77 K have been carried out to evaluate the binding parameters in the binary system consisting of BLGA and tetracycline hydrochloride (TC). Low-temperature phosphorescence studies at 77 K of pure BLGA confirm Trp 19 to be the emitting residue, while Trp 61 is silent. Enhancement of BLGA phosphorescence emission in the ternary system at 77 K indicates that Trp 19 is very close to Eu(III) in the EuTC complex. The molecular docking results further confirm that TC binds close to Trp 19 in a hydrophobic domain. The results thus obtained can provide guidelines to design and synthesize target-oriented drugs as well as suitable bio-probes.
三元体系包括在生理 pH 值（pH = 7.4）的水溶液缓冲液中，Eu(III)配合物盐酸四环素（EuTC）与牛β-乳球蛋白变体 A（BLGA）结合，旨在利用增强的“天线效应”定位结合药物并找到结合位点的微环境。在室温及 77 K 下进行稳态和时间分辨发射研究，以评估二元体系中 BLGA 和盐酸四环素（TC）的结合参数。纯 BLGA 在 77 K 下的低温磷光研究证实色氨酸 19 是发光残基，而色氨酸 61 是沉默的。三元体系在 77 K 下 BLGA 磷光发射的增强表明色氨酸 19 非常接近 EuTC 配合物中的 Eu(III)。分子对接结果进一步证实，TC 结合在疏水区中靠近色氨酸 19。因此，所得结果可以为设计和合成靶向药物以及合适的生物探针提供指导。
