SRICT-Institute of Science and Research, UPL University of Sustainable Technology, Block No: 402, Ankleshwar - Valia Rd, Vataria, Gujarat 393135, India.
Department of Chemistry, University of Science, Chandigarh University, Gharuan, Mohali, Punjab, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Feb 5;286:122015. doi: 10.1016/j.saa.2022.122015. Epub 2022 Oct 19.
The binding interaction of surfactant cobalt(III) complex, cis-Co(bpy)(HA), in which bpy is 2,2-bipyridine and HA is hexadecylamine or cetylamnine with DNA was through intercalative mode via the long aliphatic chains present in the ligands. The binding was investigated by various techniques, electronic absorption, fluorescence spectroscopy, circular dichroism (CD), cyclic voltametry (CV) and viscosimetry measurements. The spectroscopic studies together with cyclic voltammetry and viscosity experiments support that the surfactant cobalt(III) complex binds to calf thymus DNA by intercalation through the aliphatic chain present in the complex into the base pairs of DNA. The presence of bipyridine ligand with larger π-frame work may also enhance intercalation. UV-vis., spectrum showed 4 nm bathochromic shift of the absorption band at 352 nm along with significant hypochromicity for the absorption band of the complex. The intrinsic binding constants(at below and above CMC are K = 2.41 × 10M, K = 3.12 × 10M respectively) is more in keeping with intercalators and suggests this binding mode. The viscosity measurements showed that the surfactant cobalt(III) complex-DNA interaction can be hydrophobic and confirm intercalation. Moreover, the complex induced detectable changes in the CD spectrum of CT-DNA. Competitive binding study with ethidium bromide (EB) shows that the surfactant complex exhibits the ability to displace the DNA-bound EB indicating that the complex binds to DNA in strong competition with EB for the intercalative binding site. Also, CV results confirm this mode because, with increasing the CT-DNA concentration, shift to higher potential was observed. Besides the effect of binding of surfactant cobalt(III) complex to DNA in presence of β-cyclodextrin has also studied. This binding of the surfactant cobalt(III) complex in presence of β-cyclodextrin medium has been prevented (at below and above CMC are K = 5.45 × 10M, K = 6.92 × 10M respectively) due to the incorporation of the aliphatic chains into the cavity of β-cyclodextrin. In presence of β-cyclodextrin the binding occur through surface and (or) groove binding can be attributed to the inclusion of the long aliphatic chain that is present in one of the ligands into cyclodextrin.
表面活性剂钴（III）配合物 cis-Co(bpy)(HA) 与 DNA 的结合相互作用通过配体中存在的长脂肪链以嵌入模式进行。通过各种技术、电子吸收、荧光光谱、圆二色性 (CD)、循环伏安法 (CV) 和粘度测量研究了结合。光谱研究以及循环伏安法和粘度实验表明，表面活性剂钴（III）配合物通过存在于配合物中的脂肪链进入 DNA 的碱基对，通过嵌入与小牛胸腺 DNA 结合。具有更大π-框架的联吡啶配体的存在也可能增强嵌入作用。紫外可见光谱显示，吸收带在 352nm 处发生 4nm 红移，同时配合物的吸收带显著减色。低于和高于 CMC 时的固有结合常数（K=2.41×10M，K=3.12×10M）更符合嵌入剂，并表明这种结合模式。粘度测量表明，表面活性剂钴（III）配合物-DNA 相互作用可能是疏水性的，并证实了嵌入作用。此外，该配合物诱导 CT-DNA 的 CD 光谱发生可检测的变化。与溴化乙锭 (EB) 的竞争结合研究表明，表面活性剂配合物具有取代 DNA 结合的 EB 的能力，表明该配合物与 DNA 以强烈的竞争方式结合，与 EB 争夺嵌入结合位点。此外，CV 结果证实了这种模式，因为随着 CT-DNA 浓度的增加，观察到向更高电位的位移。此外，还研究了β-环糊精存在下表面活性剂钴（III）配合物与 DNA 的结合。由于脂肪链被纳入β-环糊精的空腔，表面活性剂钴（III）配合物在β-环糊精介质中的这种结合（低于和高于 CMC 时的 K=5.45×10M，K=6.92×10M）被阻止。β-环糊精存在下的结合可以归因于存在于配体之一中的长脂肪链被纳入环糊精，通过表面和（或）沟槽结合发生。
