Henan Key Laboratory of Ion-Beam Bioengineering, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China.
School of Food and Biological Engineering, Henan University of Animal Husbandry and Economy, Zhengzhou 450047, China.
Biomolecules. 2023 Jun 8;13(6):964. doi: 10.3390/biom13060964.
Z-DNA refers to the left-handed double-helix DNA that has attracted much attention because of its association with some specific biological functions. However, because of its low content and unstable conformation, Z-DNA is normally difficult to observe or identify. Up to now, there has been a lack of unified or standard analytical methods among diverse techniques for probing Z-DNA and its transformation conveniently. In this work, NaCl, MgCl, and ethanol were utilized to induce d(GC) from B-DNA to Z-DNA in vitro, and Fourier transform infrared (FTIR) spectroscopy was employed to monitor the transformation of Z-DNA under different induction conditions. The structural changes during the transformation process were carefully examined, and the DNA chirality alterations were validated by the circular dichroism (CD) measurements. The Z-DNA characteristic signals in the 1450 cm-900 cm region of the d(GC) infrared (IR) spectrum were observed, which include the peaks at 1320 cm, 1125 cm and 925 cm, respectively. The intensity ratios of A/A, A/A, and A/A increased with Z-DNA content in the transition process. Furthermore, compared with the CD spectra, the IR spectra showed higher sensitivity to Z-DNA, providing more information about the molecular structure change of DNA. Therefore, this study has established a more reliable FTIR analytical approach to assess BZ DNA conformational changes in solutions, which may help the understanding of the Z-DNA transition mechanism and promote the study of Z-DNA functions in biological systems.
Z-DNA 是指左手双螺旋 DNA，由于其与某些特定的生物功能有关，因此引起了广泛关注。然而，由于其含量低且构象不稳定，通常难以观察或识别 Z-DNA。到目前为止，不同技术探测 Z-DNA 及其转化的方法缺乏统一或标准。在这项工作中，我们利用 NaCl、MgCl 和乙醇在体外将 d(GC)从 B-DNA 诱导为 Z-DNA，并用傅里叶变换红外（FTIR）光谱监测不同诱导条件下 Z-DNA 的转化。仔细检查了转化过程中的结构变化，并通过圆二色性（CD）测量验证了 DNA 手性的改变。在 d(GC)红外（IR）光谱的 1450 cm-900 cm 区域观察到 Z-DNA 的特征信号，包括分别在 1320 cm、1125 cm 和 925 cm 处的峰。在转变过程中，A/A、A/A 和 A/A 的强度比随着 Z-DNA 含量的增加而增加。此外，与 CD 光谱相比，IR 光谱对 Z-DNA 具有更高的灵敏度，提供了有关 DNA 分子结构变化的更多信息。因此，本研究建立了一种更可靠的 FTIR 分析方法来评估溶液中 BZ DNA 的构象变化，这可能有助于理解 Z-DNA 转变机制，并促进对生物系统中 Z-DNA 功能的研究。
