Department of Chemistry, Bharathiar University, Coimbatore, Tamil Nadu, India.
Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu, India.
Photochem Photobiol. 2017 Jul;93(4):1043-1056. doi: 10.1111/php.12744. Epub 2017 Apr 25.
The nature of binding mechanism of toluidine blue O (TBO) with chicken egg white lysozyme was studied comprehensively by various spectroscopic and computational methods. Both steady state and time-resolved fluorescence studies unambiguously point to the prevalence of static quenching mechanism in lysozyme-TBO system. Thermodynamic parameters revealed that the association of TBO with lysozyme was a spontaneous process in which hydrophobic and hydrogen bond interactions played a pivotal role in the binding process. The secondary and tertiary conformational changes of lysozyme in the presence of TBO were unraveled using absorption, Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) techniques. Molecular docking studies of lysozyme-TBO system substantiated the findings of site marker experiment and revealed TBO adjacent to Trp-63 and Trp-108 residues of lysozyme. Molecular dynamics (MD) simulation studies of lysozyme-TBO system indicate a stable and effective complexation of TBO with lysozyme. It is hoped that the results presented here will enable further understanding of TBO toxicity.
通过各种光谱和计算方法，全面研究了甲苯胺蓝 O（TBO）与鸡卵清白蛋白溶菌酶的结合机制。稳态和时间分辨荧光研究都明确指出，在溶菌酶-TBO 体系中，普遍存在静态猝灭机制。热力学参数表明，TBO 与溶菌酶的结合是一个自发的过程，其中疏水相互作用和氢键相互作用在结合过程中起着关键作用。利用吸收、傅里叶变换红外光谱（FT-IR）和圆二色性（CD）技术揭示了 TBO 存在下溶菌酶的二级和三级构象变化。溶菌酶-TBO 体系的分子对接研究证实了位点标记实验的结果，并揭示了 TBO 与溶菌酶的色氨酸残基 63 和 108 相邻。溶菌酶-TBO 体系的分子动力学（MD）模拟研究表明，TBO 与溶菌酶的结合是稳定有效的。希望这里提出的结果将有助于进一步了解 TBO 的毒性。
