In this work we have investigated influence of divalent Mn ions on the structure of dsDNA utilizing Fourier transform infrared spectroscopy on DNA thin films obtained from sodium and manganese salt DNA (Na-DNA and Mn-DNA) in manganese chloride solutions and manganese salt DNA in pure water. In the range of low Mn content, 0.0067 ≤ r = [manganese]/[phosphate] ≤ 0.5, the difference between vibrational spectrum of thin films Na-DNA and Mn-DNA is revealed. Former one is more influenced by an increase of Mn content and shows stabilization of B form dsDNA, while in thin films Mn-DNA in MnCl₂ and Mn-DNA in pure water, B form is stable even at the lowest Mn content. An increase of Mn content over r > 0.5 induces spectral changes in both base and phosphate region that fully actualize once intrinsic Na⁺ ions are completely suppressed by divalent Mn²⁺ ions. Finally, the difference in vibrational spectrum of Na-DNA and Mn-DNA at high Mn concentrations almost completely disappears. The observed results consistently demonstrate that Mn²⁺ ions interact with both base sites of DNA (primarily C8N7 sites of guanine and adenine) and phosphate groups; both asymmetric and symmetric PO₂ vibrations show prominent blue shift in the presence of high Mn content, while B conformation remains stable. Nature of the Mn cation-DNA interaction seems to be electrostatic and water mediated, as demonstrated by almost complete reversal of perturbations in base and sugar-phosphate region in thin films Mn-DNA in pure water.

在这项工作中，我们利用傅立叶变换红外光谱技术研究了氯化锰溶液中的钠和锰盐DNA（Na-DNA和Mn-DNA）和锰盐DNA中获得的DNA薄膜，并研究了二价Mn离子对dsDNA结构的影响。纯净水。在低Mn含量的范围内，0.0067≤r＝ [锰] / [磷酸盐]≤0.5，揭示了薄膜Na-DNA和Mn-DNA的振动光谱之间的差异。前者受Mn含量增加的影响更大，并且表现出B形式的dsDNA稳定，而在薄膜中MnCl _2中的Mn-DNA和纯水中的Mn-DNA中，即使在最低Mn含量下，B形式也是稳定的。锰含量比r增加 > 0.5会引起碱基区域和磷酸盐区域的光谱变化，一旦固有的Na ⁺离子被二价Mn ²⁺离子完全抑制，该变化就会完全实现。最后，在高锰浓度下Na-DNA和Mn-DNA振动光谱的差异几乎完全消失了。观察到的结果一致地表明，Mn ²⁺离子与DNA的碱基（主要是鸟嘌呤和腺嘌呤的C8 N7碱基）和磷酸基团相互作用。不对称和对称PO ₂锰含量高时，振动显示出明显的蓝移，而B构象保持稳定。Mn阳离子-DNA相互作用的性质似乎是静电和水介导的，这可以通过纯水中薄膜Mn-DNA的碱基和糖-磷酸盐区域的扰动几乎完全逆转来证明。