The effects of tetrakis(1-methylpyridinium-4-yl)porphyrinatomercury(II) [ Hg ( TMPyP )]4+(6) along with [ Pb ( TMPyP )]4+(7), [ Cd ( TMPyP )]4+(8), and [ H2( TMPyP )]4+(1) (free base porphyrin) on DNA cleavage by Haemophilus aegyptius (HaeIII) have been studied using gel electrophoresis, UV-vis absorption spectroscopy, and circular dichroism (CD) spectroscopy. The gel electrophoresis results indicate that in the absence of 6, HaeIII restriction enzyme could not cleave plasmid DNA at a low concentration of 0.2 units μl-1after 1 h incubation at 37 °C. However, DNA cleavage occurred in the presence of 6 at the concentrations of 1.0 × 10-6and 1.0 × 10-7M and 0.2 units μl-1of HaeIII under the same conditions. In addition, acceleration of DNA cleavage occurred at a higher concentration of HaeIII (0.4 units μl-1) in the presence of a wider concentration range of 6 from 1.0 × 10-5to 1.0 × 10-7M . 8, 7, and 1 could not enhance DNA cleavage in the presence of HaeIII (0.2 units μl-1). However, when the concentration of HaeIII was increased to 0.4 units μl-1, only 8 inhibited DNA cleavage by HaeIII at higher concentrations (1.0 × 10-5-10-6M ) whereas 6, 7, and 1 did not. The UV-vis and CD spectroscopic results indicate that these porphyrins interact differently with DNA based on their binding modes. 6 enhanced DNA cleavage due to the synergistic effect of the Hg2+ions and the free base porphyrin 1 that dissociated from the mercury(II) porphyrin complex upon binding to DNA which resulted in the enhanced transformation of the DNA conformation from the original B-form to a Z-like conformation, while 8 inhibited HaeIII activity at higher concentrations and 7 and 1 neither enhanced nor inhibited DNA cleavage. A mechanism for this phenomenon is suggested.

中文翻译：

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四阳离子汞(II)、镉(II)和铅(II)卟啉与DNA的相互作用及其对DNA裂解的影响

四（1-甲基吡啶鎓-4-基）卟啉汞（II）[Hg（TMPyP）]的作用4+(6) 连同 [ Pb ( TMPyP )]4+(7), [ 镉 ( TMPyP )]4+(8) 和 [ H2(TMPyP)]4+(1) (游离碱基卟啉) 对埃及嗜血杆菌 (HaeIII) 对 DNA 的切割作用已使用凝胶电泳、紫外-可见吸收光谱和圆二色 (CD) 光谱进行了研究。凝胶电泳结果表明，在没有 6 的情况下，HaeIII 限制性内切酶在 0.2 单位 μl 的低浓度下不能切割质粒 DNA-1在 37°C 孵育 1 小时后。然而，在 1.0 × 10 浓度的 6 存在下发生 DNA 切割-6和 1.0 × 10-7M 和 0.2 单位 μl-1HaeIII 在相同条件下。此外，在较高浓度的 HaeIII（0.4 单位 μl-1) 在 6 从 1.0 × 10 更宽的浓度范围存在的情况下-5至 1.0 × 10-7米。8、7 和 1 在 HaeIII（0.2 单位 μl-1）。然而，当 HaeIII 的浓度增加到 0.4 单位 μl-1, 只有 8 个抑制 HaeIII 在较高浓度 (1.0 × 10-5-10-6M ) 而 6、7 和 1 没有。UV-vis 和 CD 光谱结果表明，这些卟啉根据它们的结合模式与 DNA 的相互作用不同。6 由于 Hg 的协同作用增强了 DNA 切割2+离子和游离碱基卟啉 1 在与 DNA 结合后从汞 (II) 卟啉复合物中解离，导致 DNA 构象从原始 B 型向 Z 型构象的转化增强，而 8 抑制 HaeIII 活性更高的浓度和 7 和 1 既不增强也不抑制 DNA 切割。提出了这种现象的机制。