Solution structure of a europium–nicotianamine complex supports that phytosiderophores bind lanthanides
Solution structure of a europium–nicotianamine complex supports that phytosiderophores bind lanthanides
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铕-烟草胺复合物的溶液结构支持植物铁载体结合镧系元素
DOI：
10.1039/d0cp06150f
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发表时间：
2021
影响因子：
3.3
通讯作者：
Cantu, David C.
中科院分区：
文献类型：
--
作者：
Kaliakin, Danil S.;Sobrinho, Josiane A.;Monteiro, Jorge H.;de Bettencourt-Dias, Ana;Cantu, David C.
我们报道了用密度泛函理论从头算分子动力学模拟预测的铕-烟胺配合物的溶液结构。发射光谱和激发光谱显示，在烟碱存在的情况下，Eu3+配位环境发生了变化，表明形成了配合物，如计算预测的Eu3+ -烟碱配合物结构。我们在周期盒中模拟了带有明确水分子的Eu3+配体配合物，有效地模拟了溶液相。我们的模拟考虑了可能的化学事件（例如配位键的形成，质子化状态的变化，电荷转移），以及配体的柔韧性和溶剂的重排。我们的计算方法正确地预测了Eu3+ -乙二胺四乙酸配合物的溶液结构，在实验测量值的0.05 Å范围内，支持了Eu3+ -烟胺配合物预测溶液结构的保真度。我们还对众所周知的Eu3+ -乙二胺四乙酸配合物进行了发射光谱和激发光谱测量，以验证我们的实验方法。分析了Eu3+ -烟胺配合物的电子结构，更详细地描述了配合物。烟胺是植物铁载体的代谢前体，其结构与植物铁载体非常相似，而植物铁载体负责植物对金属的吸收。虽然烟草胺与铕结合的知识并不能决定植物如何从环境中吸收稀土，但它有力地支持了植物铁载体与镧系元素结合的说法。
We report the solution structure of a europium-nicotianamine complex predicted from ab initio molecular dynamics simulations with density functional theory. Emission and excitation spectroscopy show that the Eu3+ coordination environment changes in the presence of nicotianamine, suggesting complex formation, such as what is seen for the Eu3+–nicotianamine complex structure predicted from computation. We modeled Eu3+–ligand complexes with explicit water molecules in periodic boxes, effectively simulating the solution phase. Our simulations consider possible chemical events (e.g. coordination bond formation, protonation state changes, charge transfers), as well as ligand flexibility and solvent rearrangements. Our computational approach correctly predicts the solution structure of a Eu3+–ethylenediaminetetraacetic acid complex within 0.05 Å of experimentally measured values, backing the fidelity of the predicted solution structure of the Eu3+–nicotianamine complex. Emission and excitation spectroscopy measurements were also performed on the well-known Eu3+–ethylenediaminetetraacetic acid complex to validate our experimental methods. The electronic structure of the Eu3+–nicotianamine complex is analyzed to describe the complexes in greater detail. Nicotianamine is a metabolic precursor of, and structurally very similar to, phytosiderophores, which are responsible for the uptake of metals in plants. Although knowledge that nicotianamine binds europium does not determine how plants uptake rare earths from the environment, it strongly supports that phytosiderophores bind lanthanides.