在 POM 催化的 DNA 模型水解中探索催化活性物质**,Chemistry - A European Journal

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在 POM 催化的 DNA 模型水解中探索催化活性物质**
Chemistry - A European Journal ( IF 3.9 ) Pub Date : 2021-04-22 , DOI: 10.1002/chem.202004989
Frederico F Martins ₁ , Ángel Sánchez-González ₁ , Jose Lanuza _{2,

3} , Haralampos N Miras ₄ , Xabier Lopez _{2,

3} , Nuno A Bandeira ₁ , Adrià Gil _{1,

5}

Affiliation

磷酸酯水解是 DNA 修复的重要化学步骤。磷酸酯的一种典型分子模型是对硝基苯磷酸盐 (pNPP)。先前已经表明，分子金属氧化物[Mo ₇ O ₂₄ ] ^{6- 的存在}可以通过聚氧钼酸盐骨架的部分分解来催化pNPP的水解，产生[(PO ₄ ) ₂ Mo ₅ O ₁₅ ] ^6-产品。使用电喷雾电离质谱 (ESI-MS) 对催化系统进行实时监测，可以一瞥反应混合物中存在的物质，并确定潜在的催化候选物。根据获得的光谱数据，进行密度泛函理论 (DFT) 计算以表征假设中间体 [Mo ₅ O ₁₅ (pNPP) ₂ (H ₂ O) ₆ ] ⁶⁻，其在假设条件下需要形成转型。令人惊讶的是，我们的结果指向 [Mo ₂ O ₈ ] ⁴⁻阴离子的二聚体[Mo ₇O ₂₄ ] ^6-作为参与 pNPP 水解的活性催化物质，而不是最初假设的 {Mo ₅ O ₁₅ } 物质。进行了一项类似的研究，涉及相同的物种，但用 W 代替 Mo。涉及 W 物种的机制显示出更高的势垒和不太稳定的产物，这与实验结果中发现的非催化效应一致。

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Probing the Catalytically Active Species in POM-Catalysed DNA-Model Hydrolysis**

Phosphoester hydrolysis is an important chemical step in DNA repair. One archetypal molecular model of phosphoesters is para-nitrophenylphosphate (pNPP). It has been shown previously that the presence of molecular metal oxide [Mo₇O₂₄]⁶⁻ may catalyse the hydrolysis of pNPP through the partial decomposition of polyoxomolybdate framework resulting in a [(PO₄)₂Mo₅O₁₅]⁶⁻ product. Real-time monitoring of the catalytic system using electrospray ionisation mass spectrometry (ESI-MS) provided a glance into the species present in the reaction mixture and identification of potential catalytic candidates. Following up on the obtained spectrometric data, Density Functional Theory (DFT) calculations were carried out to characterise the hypothetical intermediate [Mo₅O₁₅(pNPP)₂(H₂O)₆]⁶⁻ that would be required to form under the hypothesised transformation. Surprisingly, our results point to the dimeric [Mo₂O₈]⁴⁻ anion resulting from the decomposition of [Mo₇O₂₄]⁶⁻ as the active catalytic species involved in the hydrolysis of pNPP rather than the originally assumed {Mo₅O₁₅} species. A similar study was carried out involving the same species but substituting Mo by W. The mechanism involving W species showed a higher barrier and less stable products in agreement with the non-catalytic effect found in experimental results.

更新日期：2021-06-21

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