Department of Physical Chemistry, University of Madras, Chennai, India.
School of Chemistry, Bharathidasan University, Tiruchirappalli, India.
J Biomol Struct Dyn. 2021 Mar;39(5):1535-1546. doi: 10.1080/07391102.2020.1733664. Epub 2020 Mar 2.
Biophysical interaction of amphiphilic fluorescent surfactant-ruthenium(II) complexes and its precursor ruthenium(II) complexes with drug carrying proteins such as bovine and human serum albumins (BSA and HSA) have been studied through the UV-visible absorption, fluorescence and circular dichroism spectroscopic techniques to correlate the impact of head and tail groups of the metallosurfactants towards the designing of metallodrugs for the biomedical applications. The obtained results showed that both precursor- and surfactant-ruthenium(II) complexes interact with BSA/HSA via ground state protein-complex formation and their quenching follows the static mechanism. The extent of protein quenching and binding parameters resulted that the surfactant-ruthenium(II) complexes effectively interact with protein compared to their precursor-ruthenium(II) complexes, and also those interaction have greatly influenced by the change in the head group size compared to change in the tail group length. Interestingly on increasing the temperature, the protein-complex binding strength was decreased for the precursor-ruthenium(II) complexes, those increased for the surfactant-ruthenium(II) complexes, probably due to the respective involvement of electrostatic and hydrophobic interactions as supported by the thermodynamics of protein-complex interaction. Moreover, the results from UV-visible, synchronous and circular dichroism studies confirmed the occurrence of conformational and micro environmental changes in BSA/HSA upon binding with these complexes. It is also noted that HSA has more binding affinity with surfactant-ruthenium(II) complexes compared to BSA. The free radical scavenging ability against DPPH, ABTS, NO and superoxide free radical assays suggested that surfactant-ruthenium(II) complexes have better free radical scavenging ability compared to precursor-ruthenium(II) complexes.Communicated by Ramaswamy H. Sarma.
两亲性荧光表面活性剂-钌（II）配合物及其前体钌（II）配合物与载药蛋白（如牛血清白蛋白（BSA）和人血清白蛋白（HSA））的生物物理相互作用已通过紫外-可见吸收、荧光和圆二色光谱技术进行了研究，以关联头基和尾基对金属表面活性剂的影响，为生物医学应用设计金属药物。所得结果表明，前体-和表面活性剂-钌（II）配合物均通过基态蛋白-配合物形成与 BSA/HSA 相互作用，其猝灭遵循静态机制。蛋白质猝灭的程度和结合参数表明，与前体-钌（II）配合物相比，表面活性剂-钌（II）配合物能有效地与蛋白质相互作用，而且与尾基长度的变化相比，头基大小的变化对相互作用有很大影响。有趣的是，随着温度的升高，前体-钌（II）配合物的蛋白质-配合物结合强度降低，而表面活性剂-钌（II）配合物的结合强度增加，这可能是由于静电和疏水相互作用的分别参与，这得到了蛋白质-配合物相互作用热力学的支持。此外，紫外-可见、同步和圆二色研究的结果证实了这些配合物与 BSA/HSA 结合时构象和微环境的变化。还注意到 HSA 与表面活性剂-钌（II）配合物的结合亲和力大于 BSA。对 DPPH、ABTS、NO 和超氧自由基的自由基清除能力测定表明，与前体-钌（II）配合物相比，表面活性剂-钌（II）配合物具有更好的自由基清除能力。
