Activity difference between alpha-COOH and beta-COOH in N-phosphorylaspartic acids |
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Authors: | Chen Zhong-Zhou Tan Bo Li Yan-Mei Zhao Yu-Fen Tong Yu-Feng Wang Jin-Feng |
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Affiliation: | Key Laboratory for Bioorganic Phosphorus Chemistry of Education Ministry, Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China. |
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Abstract: | N-phosphorylamino acids are chemically active species that have many biomimic activities. alpha-COOH in amino acids and peptides behaviors rather differently than beta-COOH in many biochemical processes and takes a more important role in the origin of life. Activity differences between alpha-COOH and beta-COOH in the peptide formation of phosphoryl amino acids are studied by 1D, 2D NMR techniques and by ab initio and density functional theory (DFT) calculations in this paper. Phosphoryl dipeptide is formed directly from phosphoryl aspartic acids without any coupling reagents. Only the alpha-dipeptide ester is observed by 1D (1)H, (13)C, and (31)P NMR and 2D NMR. In the ab initio and DFT calculations, the pentacoordinate phosphorane intermediates containing five-membered rings are predicted to be more favored than those with six-membered rings. Both the experimental results and the theoretical calculations suggest that only the alpha-COOH group is activated by N-phosphorylation in N-phosphorylaspartic acid under mild conditions. |
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