Catalyzed Peptide Bond Formation in the Gas Phase. Role of Bivalent Cations and Water in Formation of 2-Aminoacetamide from Ammonia and Glycine and in Dimerization of Glycine
Catalyzed Peptide Bond Formation in the Gas Phase. Role of Bivalent Cations and Water in Formation of 2-Aminoacetamide from Ammonia and Glycine and in Dimerization of Glycine
复制标题
气相中催化肽键的形成。
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
B. Rode
中科院分区：
文献类型：
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作者：
M. Remko;B. Rode
氨和甘氨酸形成2-氨基乙酰胺以及两个甘氨酸分子在有和没有Mg 2+、Cu 2+和Zn 2+阳离子作为催化剂的情况下形成N-甘氨酰甘氨酸已经被研究作为肽键形成的模型反应，使用B3 LYP泛函，6−311+G（d，p）和6− 31 G（d）基组。B3 LYP方法也被用来表征9个气相配合物的中性甘氨酸，其酰胺（2-氨基乙酰胺），和N-甘氨酰甘氨酸与刘易斯酸Mg 2+，Cu 2+，和Zn 2+，分别。此外，还研究了甘氨酸、2-氨基乙酰胺和N-甘氨酰甘氨酸的金属配位络合物的气相水合。最后，确定了水对金属配位络合物的结构和反应性的影响。焓和吉布斯自由能的固定点的每个反应已被计算，以确定热力学的反应研究。与未配位的2-氨基乙酰胺键形成相比，Mg 2+，Cu 2+和Zn 2+离子配位的甘氨酸-氨和甘氨酸-甘氨酸反应的反应动力学和吉布斯自由能显著降低。二肽的形成是比从甘氨酸产生简单的2-氨基乙酰胺更放热的过程。过渡金属离子Cu ~（2+）和Zn ~（2+）的能量效应具有相似的强度，并且比Mg ~（2+）的能量效应更显著。酰胺的碱性顺序为NH_2CH_2CO_2H <NH_2CH_2CONH_2 <NH_2CH_2CONHCH_2CO_2H。随着Mg ~（2+）<Zn ~（2+）<Cu ~（2+），金属离子-酰胺络合物的相互作用势和吉布斯自由能增大。在反应物（甘氨酸）和反应产物（2-氨基乙酰胺，N-甘氨酰甘氨酸）中，二水合导致分叉金属-酰胺键的强度显著降低（约200-500 kJ·mol-1）。溶剂效应也降低了所研究的反应的焓和吉布斯能。
The formation of 2-aminoacetamide from ammonia and glycine and N-glycylglycine from two glycine molecules with and without Mg2+, Cu2+, and Zn2+ cations as catalysts have been studied as model reactions for peptide bond formation using the B3LYP functional with 6−311+G(d,p) and 6−31G(d) basis sets. The B3LYP method was also used to characterize the nine gas–phase complexes of neutral glycine, its amide (2-aminoacetamide), and N-glycylglycine with Lewis acids Mg2+, Cu2+, and Zn2+, respectively. Further, the gas-phase hydration of metal-coordinated complexes of glycine, 2-aminoacetamide, and N-glycylglycine was also investigated. Finally, the effect of water on the structure and reactivity of the metal coordinated complexes was determined. Enthalpies and Gibbs energies for the stationary points of each reaction have been calculated to determine the thermodynamics of the reactions investigated. A substantial decrease in reaction enthalpies and Gibbs energies was found for glycine–ammonia and glycine–glycine reactions coordinated by Mg2+, Cu2+, and Zn2+ ions compared to those of the uncoordinated 2-aminoacetamide bond formation. The formation of a dipeptide is a more exothermic process than the creation of simple 2-aminoacetamide from glycine. The energetic effect of the transition metal ions Cu2+ and Zn2+ is of similar strength and more pronounced than that of the Mg2+ cation. The basicity order of the amides investigated shows the order: NH2CH2CO2H < NH2CH2CONH2 < NH2CH2CONHCH2CO2H. Interaction enthalpies and Gibbs energies of metal ion–amide complexes increase as Mg2+<Zn2+<Cu2+. In both reactant (glycine) and reaction products (2-aminoacetamide, N-glycylglycine) dihydration caused considerable reduction (about 200–500 kJ-mol−1) of the strength of the bifurcated metal–amide bonds. Solvent effects also reduce the reaction enthalpy and Gibbs energy of reactions under study.