Qin Pengfei, Pan Xingren, Liu Rutao, Qiu Jicai, Fang Xiaoyan
College of Resources and Environment, Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, Linyi University, Linyi, China.
School of Physics and Electronic Engineering, Linyi University, Linyi, China.
J Mol Recognit. 2017 Dec;30(12). doi: 10.1002/jmr.2647. Epub 2017 Jun 13.
Ciprofloxacin (CPFX) and enrofloxacin (ENFX) are 2 representatives of widely used fluoroquinolones (FQs) with many human and veterinary applications. The residues of FQs in the environment are potentially harmful. Recently, great concern has been paid to their persistence and fate in the environment because of the potential adverse effects on humans and ecosystem functions. In the present study, we examined the interactions of bovine hemoglobin (BHb) with these 2 FQs by means of multiple spectroscopic and molecular docking methods under physiological conditions. The experimental results revealed that both FQs could bind with BHb to form complexes mainly through electrostatic interactions. And CPFX posed more of an affinity threat to BHb than ENFX. On the basis of molecular docking, both FQs could bind into the central cavity of BHb and interact with the residue Trp 37, resulting in the remarkable fluorescence quenching of protein. Additionally, as shown by the synchronous fluorescence, UV-visible absorption and circular dichroism data, both CPFX and ENFX could lead to the conformational and microenvironmental changes of BHb, which may affect its physiological functions. The work is beneficial for understanding the biological toxicity of FQs in vivo.
环丙沙星（CPFX）和恩诺沙星（ENFX）是广泛应用于人类和兽医领域的氟喹诺酮类药物（FQs）的两种代表药物。环境中氟喹诺酮类药物的残留具有潜在危害。最近，由于其对人类和生态系统功能的潜在不利影响，人们对它们在环境中的持久性和归宿极为关注。在本研究中，我们在生理条件下通过多种光谱和分子对接方法研究了牛血红蛋白（BHb）与这两种氟喹诺酮类药物的相互作用。实验结果表明，两种氟喹诺酮类药物都能与BHb结合形成复合物，主要通过静电相互作用。并且CPFX对BHb的亲和力威胁比ENFX更大。基于分子对接，两种氟喹诺酮类药物都能结合到BHb的中央腔中，并与残基Trp 37相互作用，导致蛋白质显著的荧光猝灭。此外，同步荧光、紫外可见吸收和圆二色性数据表明，CPFX和ENFX都能导致BHb的构象和微环境变化，这可能会影响其生理功能。这项工作有助于理解氟喹诺酮类药物在体内的生物毒性。
