Abstract：
Human serum albumin (HSA) effectively binds to compounds having different molecular weight and thus facilitates their distribution in the living organisms. Thus, the binding interactions between a potential antibacterial drug (levofloxacin) and synthesized choline based levofloxacinate conjugates with HSA have been explored. The binding efficacy and mechanism were explored by utilizing different spectroscopic techniques; UV-Visible, steady state fluorescence, time resolved fluorescence and esterase-like activity. The interactions between the ligands and protein were electrostatic as well as hydrophobic in nature. The influence of different ligands having different alkyl chain shows quenching of the fluorescence emission of HSA. The spontaneous binding/quenching of HSA with ligands was static in nature, validated by steady state and time resolved fluorescence spectroscopy. Also, the impact of these ligands on the conformation of the native HSA structure was evaluated by using circular dichroism spectroscopy. In combination to the structural change study, the native protein functionality was observed (in terms of \'esterase-like activity\') which has been found to be on lower side due to ligand binding. Further, we have performed the reverse study to check the impact of HSA on the fluorescent fluoroquinolone drug. The current study may prove helpful in elucidating the chemico-biological interactions which may prove useful in the pharmaceuticals, pharmacology, and different biochemistry fields.
摘要：
人血清白蛋白(HSA)有效地结合具有不同分子量的化合物,从而促进它们在活生物体中的分布。因此，已经探索了潜在的抗菌药物（左氧氟沙星）与合成的基于胆碱的左氧氟沙星与HSA缀合物之间的结合相互作用。利用不同的光谱技术探索了结合功效和机理；紫外可见，稳态荧光，时间分辨荧光和酯酶样活性。配体和蛋白质之间的相互作用本质上是静电的和疏水的。具有不同烷基链的不同配体的影响显示HSA的荧光发射的猝灭。HSA与配体的自发结合/猝灭本质上是静态的，通过稳态和时间分辨荧光光谱验证。此外，这些配体对天然HSA结构构象的影响通过使用圆二色性光谱学来评估。结合结构变化研究，观察到天然蛋白质功能（就“酯酶样活性”而言），由于配体结合，已发现其处于较低水平。Further,我们进行了反向研究,以检查HSA对荧光氟喹诺酮类药物的影响.当前的研究可能有助于阐明化学-生物相互作用，这可能证明对药物有用，药理学,和不同的生物化学领域。
