Ali Mohd Sajid, Al-Lohedan Hamad A
Surfactant Research Chair, Department of Chemistry, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
ACS Omega. 2020 Apr 16;5(16):9131-9141. doi: 10.1021/acsomega.9b04291. eCollection 2020 Apr 28.
Owing to the various beneficial properties of the popular spice saffron, the interaction of safranal, a secondary metabolite of the former, with hen egg white lysozyme was investigated. The formation of a complex was evidenced by UV-visible spectroscopy. Fluorescence quenching experiments were also performed to understand the binding mechanism and to evaluate the forces involved in binding. The strong absorption of safranal in the range of excitation and emission wavelengths of lysozyme fluorescence required the correction of the inner filter effect for fluorescence spectra to obtain the apparent extent of binding. There was a considerable difference between the observed spectra and corrected spectra, and a similar observation was found in the case of synchronous fluorescence spectra. From the analysis of quenching data, it was found that the mechanism involved in quenching was static with 1:1 binding between them. The interaction was found to be driven, mainly, by hydrophobic forces and hydrogen bonding. Safranal had negligible impact on the secondary structure of lysozyme. The interaction was also studied by molecular docking, and the results were in good agreement with the results obtained experimentally. The binding site of safranal was in the big hydrophobic cavity of lysozyme. The amino acids involved in the interaction were Asp52, Ile58, Gln57, Asn59, Trp62, Trp63, Trp108, Ile98, Asp101, and Ala107.
由于广受欢迎的香料藏红花具有多种有益特性，因此对其二级代谢产物藏红花醛与鸡蛋清溶菌酶的相互作用进行了研究。紫外可见光谱法证明了复合物的形成。还进行了荧光猝灭实验，以了解结合机制并评估结合过程中涉及的作用力。藏红花醛在溶菌酶荧光激发和发射波长范围内有强烈吸收，因此需要对荧光光谱的内滤光片效应进行校正，以获得表观结合程度。观察到的光谱与校正后的光谱之间存在显著差异，同步荧光光谱也有类似现象。通过对猝灭数据的分析发现，猝灭机制为静态猝灭，二者以1:1的比例结合。发现这种相互作用主要由疏水作用力和氢键驱动。藏红花醛对溶菌酶的二级结构影响可忽略不计。还通过分子对接研究了这种相互作用，结果与实验结果高度吻合。藏红花醛的结合位点位于溶菌酶的大疏水腔内。参与相互作用的氨基酸有Asp52、Ile58、Gln57、Asn59、Trp62、Trp63、Trp108、Ile98、Asp101和Ala107。
