Hierarchical Reactivity of Enzyme-Mediated Phosphorus Recycling from Organic Mixtures by Aspergillus niger Phytase
Hierarchical Reactivity of Enzyme-Mediated Phosphorus Recycling from Organic Mixtures by Aspergillus niger Phytase
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DOI：
10.1021/acs.jafc.0c05924
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发表时间：
2021-02-24
影响因子：
6.1
通讯作者：
Aristilde，Ludmilla
中科院分区：
文献类型：
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作者：
Solhtalab，Mina;Klein，Annaleise R.;Aristilde，Ludmilla
通过磷酸酶型酶（包括植酸酶）从有机磷（Po）化合物中对无机磷（Pi）进行生物循环，是植物和微生物生物可利用磷库的重要贡献者。然而，缺乏对这些酶的混合底物反应的研究。在这里，我们探索了来自真菌黑曲霉的植酸酶提取物对异质混合物的反应性，该异质混合物除植酸盐外还含有不同结构的环境相关多聚化合物，例如核糖核苷酸和糖磷酸盐。使用高分辨率液相色谱-质谱法同时监测母体Po化合物及其副产物，我们捕获了混合物中Pi的连续底物特异性演化，多磷酸化化合物（植酸盐、二磷酸化糖以及二磷酸化和三磷酸化核糖核苷酸）的水解比单磷酸化化合物（单磷酸化糖和单磷酸化核糖核苷酸）的水解更快。酶活性位点内每种 Po 化合物的分子对接模拟揭示的相互作用机制和能量解释了实验观察到的底物层次结构。具体而言，带负电的磷酸盐部分相对于活性位点的正电势表面的有利结合方向非常重要。总的来说，我们的研究结果提供了关于植酸酶型酶在农业土壤或废物中植酸酶化合物异质组装的 Pirecycling 中广泛但分层作用的机制见解。
Biological recycling of inorganic phosphorus (Pi) from organic phosphorus (Po) compounds by phosphatase-type enzymes, including phytases, is an important contributor to the pool of bioavailable P to plants and microorganisms. However, studies of mixed-substrate reactions with these enzymes are lacking. Here, we explore the reactivity of a phytase extract from the fungusAspergillus nigertoward a heterogeneous mixture containing, in addition to phytate, different structures of environmentally relevant Pocompounds such as ribonucleotides and sugar phosphates. Using a high-resolution liquid chromatography–mass spectrometry method to monitor simultaneously the parent Pocompounds and their by-products, we captured sequential substrate-specific evolution of Pifrom the mixture, with faster hydrolysis of multiphosphorylated compounds (phytate, diphosphorylated sugars, and di- and tri-phosphorylated ribonucleotides) than hydrolysis of monophosphorylated compounds (monophosphorylated sugars and monophosphorylated ribonucleotides). The interaction mechanisms and energies revealed by molecular docking simulations of each Pocompound within the enzyme’s active site explained the substrate hierarchy observed experimentally. Specifically, the favorable orientation for binding of the negatively charged phosphate moieties with respect to the positive potential surface of the active site was important. Collectively, our findings provide mechanistic insights about the broad but hierarchical role of phytase-type enzymes in Pirecycling from the heterogeneous assembly of Pocompounds in agricultural soils or wastes.