Theoretical research on structures of gamma-aminobutyric acid and glutamic acid in aqueous conditions.
Theoretical research on structures of gamma-aminobutyric acid and glutamic acid in aqueous conditions.
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含水条件下γ-氨基丁酸和谷氨酸结构的理论研究。
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
E. Ito
中科院分区：
文献类型：
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作者：
K. Odai;T. Sugimoto;M. Kubo;E. Ito
尽管谷氨酸只比γ-氨基丁酸（GABA）多一个羧基，但这些神经递质被它们自己的特异性受体识别。为了了解受体的配体识别机制，我们必须使用从头计算确定水溶液条件下GABA和谷氨酸的几何和电子结构。结果表明，GABA的稳定结构为伸展型，对阳离子和阴离子都有吸附作用。谷氨酸只吸引阳离子，并在水性条件下以四种形式稳定：1型（延伸形式），2型（圆形形式），3型和4型（1型的扭曲形式）。前两种能量都很低，彼此之间的能量屏障估计也很小。这些结果表明，大多数游离谷氨酸以1型、2型和瞬时形式存在。因此，本研究结果表明，当我们试图阐明配体和受体之间的识别机制时，除了配体和受体的物理化学特性之外，还应考虑配体几何结构的灵活性。
Even though glutamic acid contains only one more carboxyl group than gamma-aminobutyric acid (GABA), these neurotransmitters are recognized by their own specific receptors. To understand the ligand-recognition mechanism of the receptors, we must determine the geometric and electronic structures of GABA and glutamic acid in aqueous conditions using the ab initio calculation. The results of the present study showed that the stable structure of GABA was the extended form, and it attracted both cations and anions. Glutamic acid only attracted cations and was stabilized in four forms in aqueous conditions: Type 1 (an extended form), Type 2 (a rounded form), and Types 3 and 4 (twisted forms of Type 1). The former two types had low energy and the energy barrier between them was estimated to be small. These results showed that most free glutamic acid is present as Type 1, Type 2, and transient forms. The present results therefore suggest that the flexibility of the geometric structures of ligands should be taken into account when we attempt to elucidate the mechanism of recognition between ligands and receptors, in addition to the physicochemical characteristics of ligands and receptors.