Department of Chemistry, Faculty of Arts and Sciences, Uludag University, 16059 Bursa, Turkey.
Department of Chemistry, Faculty of Arts and Sciences, Uludag University, 16059 Bursa, Turkey.
J Photochem Photobiol B. 2014 Jan 5;130:115-21. doi: 10.1016/j.jphotobiol.2013.11.001. Epub 2013 Nov 11.
The interactions of fish sperm DNA (FS-DNA) with the sodium salt of sweetener saccharin (sacH) and its copper and zinc complexes, namely [M(sac)2(H2O)4]·2H2O (M=Cu(II) or Zn(II)) were studied by using UV-Vis titration, fluorometric competition, thermal denaturation, viscosity and gel electrophoresis measurements. The intrinsic binding constants (Kb) obtained from absorption titrations were estimated to be 2.86 (±0.06)×10(4)M(-1) for Na(sac), 6.67 (±0.12)×10(4)M(-1) for Cu-sac and 4.01 (±0.08)×10(4)M(-1) for Zn-sac. The Cu-sac complex binds to FS-DNA via intercalation with a KA value of 50.12 (±0.22)×10(4)M(-1) as evidenced by competitive binding studies with ethidium bromide. Moreover, competition experiments with Hoechst 33258 are indicative of a groove binding mode of Na(sac) and Zn-sac with binding constants of 3.13 (±0.16)×10(4)M(-1) and 5.25 (±0.22)×10(4)M(-1), respectively. The spectroscopic measurements indicate a moderate DNA binding affinity of Na(sac) and its metal complexes. The suggested binding modes are further confirmed by the thermal denaturation and viscosity measurements. In addition, Cu-sac and Zn-sac show weak ability to damage to pBR322 supercoiled plasmid DNA.
采用紫外-可见滴定、荧光竞争、热变性、粘度和凝胶电泳测量研究了鱼精子 DNA (FS-DNA)与甜味剂糖精的钠盐 (sacH)及其铜和锌配合物[M(sac)2(H2O)4]·2H2O (M=Cu(II)或 Zn(II))之间的相互作用。从吸收滴定中获得的内在结合常数 (Kb) 估计为 Na(sac)为 2.86(±0.06)×10(4)M(-1)，Cu-sac 为 6.67(±0.12)×10(4)M(-1)，Zn-sac 为 4.01(±0.08)×10(4)M(-1)。Cu-sac 配合物通过嵌入与 FS-DNA 结合，KA 值为 50.12(±0.22)×10(4)M(-1)，这可以通过与溴化乙锭的竞争性结合研究来证明。此外，与 Hoechst 33258 的竞争实验表明 Na(sac)和 Zn-sac 的结合模式为沟结合，结合常数分别为 3.13(±0.16)×10(4)M(-1)和 5.25(±0.22)×10(4)M(-1)。光谱测量表明 Na(sac)及其金属配合物与 DNA 具有中等的结合亲和力。建议的结合模式通过热变性和粘度测量进一步得到证实。此外，Cu-sac 和 Zn-sac 对 pBR322 超螺旋质粒 DNA 具有较弱的损伤能力。
