Vibrational Relaxation in EDTA Is Ion-Dependent
Vibrational Relaxation in EDTA Is Ion-Dependent
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DOI：
10.1021/acs.jpca.8b06075
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发表时间：
2018-08-16
影响因子：
2.9
通讯作者：
Baiz, Carlos R.
中科院分区：
文献类型：
--
作者：
Edington, Sean C.;Baiz, Carlos R.
离子结合羧酸基团是常见的生物分子，如金属蛋白质，但离子结合的动力学方面还没有完全理解。我们提出了振动弛豫的超快光谱测量的离子配位的羧酸基团的EDTA，我们使用作为一个模型的羧酸介导的离子结合，EDTA结合一系列的二价和三价金属离子具有高亲和力。测量解释使用Redfield为基础的非谐振动弛豫模型，合理化的趋势，在振动寿命方面的振动能量转移EDTA的不对称羧酸盐伸缩振动模式和较低的模式。结果表明，离子依赖的复杂结构和动力学的变化以及常见的结构方法的时间和空间分辨率之外，并展示了如何振动弛豫测量可能有助于探索离子结合动力学的超短长度和时间尺度。
Ion binding by carboxylate groups is common in biomolecules such as metalloproteins, but dynamical aspects of ion binding are not fully understood. We present ultrafast spectroscopic measurements of vibrational relaxation in the ion-coordinating carboxylate groups of EDTA, which we use as a model of carboxylate-mediated ion binding, as EDTA binds a series of divalent and trivalent metal ions with high affinity. The measurements are interpreted using a Redfield based anharmonic model of vibrational relaxation that rationalizes trends in vibrational lifetimes in terms of vibrational energy transfer between EDTA's asymmetric carboxylate stretching vibrational modes and lower-lying modes. Results show ion-dependent changes in complex structure and dynamics well outside the temporal and spatial resolution of common structural methods and demonstrate how vibrational relaxation measurements may contribute to exploration of ion-binding dynamics on ultrashort length and time scales.