IR spectra of flavins in solution: DFT/MM description of redox effects.
IR spectra of flavins in solution: DFT/MM description of redox effects.
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DOI：
10.1021/jp111334z
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发表时间：
2011-02
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影响因子：
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通讯作者：
Benjamin Rieff;Sebastian Bauer;G. Mathias;P. Tavan
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文献类型：
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作者：
Benjamin Rieff;Sebastian Bauer;G. Mathias;P. Tavan
蓝光感光器中的功能反应通常包括呈现特征红外(IR)光谱的瞬时还原的黄素。为了达到理论上的理解，我们将密度泛函理论(DFT)应用于嵌入在水溶液的分子力学(MM)模型中的黄素自由基。将DFT/MM方法与瞬时简正模分析(INMA)相结合，计算了阴离子和中性黄素自由基的红外溶液光谱。对于一组中红外标记谱带，我们确定了由于依次向氧化黄素添加一个电子和一个质子而引起的光谱位置、强度和宽度的变化。与实验黄素自由基溶液光谱的比较表明，我们的DFT/MM-INMA方法是准确的，并允许我们指定观察到的谱带。红外光谱的INMA计算所需的室温溶剂笼系综是在MM环境下从分子动力学(MD)模拟产生的。对于溶剂化的黄素自由基，这些MD模拟采用了由DFT/MM计算得到的MM力场。
The functional reactions in blue light photoreceptors generally involve transiently reduced flavins exhibiting characteristic infrared (IR) spectra. To approach a theoretical understanding, here we apply density functional theory (DFT) to flavin radicals embedded in a molecular mechanics (MM) model of an aqueous solution. Combining a DFT/MM approach with instantaneous normal-mode analyses (INMA), we compute the IR solution spectra of anionic and neutral flavin radicals. For a set of mid-IR marker bands, we identify those changes of spectral locations, intensities, and widths, which are caused by sequentially adding an electron and a proton to the oxidized flavin. Comparisons with experimental IR solution spectra of flavin radicals show the accuracy of our DFT/MM-INMA approach and allow us to assign the observed bands. The room temperature ensembles of solvent cages required for the INMA calculations of the IR spectra are generated in an MM setting from molecular dynamics (MD) simulations. For the solvated flavin radicals, these MD simulations employ MM force fields derived from DFT/MM calculations.