Marouzi Somaye, Sharifi Rad Atena, Beigoli Sima, Teimoori Baghaee Parisa, Assaran Darban Reza, Chamani Jamshidkhan
Department of Biochemistry and Biophysics, Faculty of Sciences, Mashhad Branch, Islamic Azad University, Mashhad, Iran.
Endoscopic and Minimally Invasive Surgery Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
Int J Biol Macromol. 2017 Apr;97:688-699. doi: 10.1016/j.ijbiomac.2017.01.047. Epub 2017 Jan 20.
The purpose of this study was to determine how lomefloxacin (LMF) interacts with human holo-transferrin (HTF) in the presence of two kinds of essential and nonessential amino acids. The investigations were carried out by fluorescence spectroscopy, zeta potential and molecular modeling techniques under imitated physiological conditions. We were able to determine the number of binding sites, the drug binding affinity to HTF in the presence of essential and nonessential amino acids and the quenching source of HTF. The interaction between HTF with LMF suggested that the microenvironment of the Trp residues was altered causing a strong static fluorescence quenching in the binary and ternary systems. The results pointed at the formation of a complex in the binary and ternary systems which caused an enhancement of the RLS intensity that was analyzed using synchronous fluorescence spectroscopy. The density functional theory (DFT) was employed to determine the amino acid residues on HTF that interacted with LMF. Also, Steric and van der Waals forces as well as the contribution of small amounts of hydrogen bonds were stronger or Tyr 71 in chain (b) than for 128 Trp in chain (a) of HTF.
本研究的目的是确定洛美沙星（LMF）在两种必需氨基酸和非必需氨基酸存在的情况下如何与人类全转铁蛋白（HTF）相互作用。在模拟生理条件下，通过荧光光谱法、zeta电位法和分子模拟技术进行了研究。我们能够确定结合位点的数量、在必需氨基酸和非必需氨基酸存在的情况下药物与HTF的结合亲和力以及HTF的猝灭源。HTF与LMF之间的相互作用表明，色氨酸残基的微环境发生了改变，导致二元和三元体系中出现强烈的静态荧光猝灭。结果表明，二元和三元体系中形成了复合物，这导致了共振光散射强度的增强，使用同步荧光光谱法对其进行了分析。采用密度泛函理论（DFT）来确定HTF上与LMF相互作用的氨基酸残基。此外，空间位阻和范德华力以及少量氢键的贡献对于HTF链（b）中的Tyr 71比链（a）中的128 Trp更强。
