Chemistry Institute, University of Campinas, P.O. Box 6154, 13083-970 Campinas, Brazil.
Chemistry Institute, University of São Paulo, P.O. Box 26077, 05508-900 São Paulo, Brazil.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Apr 5;123:482-9. doi: 10.1016/j.saa.2013.12.088. Epub 2014 Jan 3.
Amino acid conformational analysis in solution are scarce, since these compounds present a bipolar zwitterionic structure ((+)H3NCHRCOO(-)) in these media. Also, intramolecular hydrogen bonds have been classified as the sole interactions governing amino acid conformational behavior in the literature. In the present work we propose phenylalanine and tyrosine methyl ester conformational studies in different solvents by (1)H NMR and infrared spectroscopies and theoretical calculations. Both experimental and theoretical results are in agreement and suggest that the conformational behavior of the phenylalanine and tyrosine methyl esters are similar and are dictated by the interplay between steric and hyperconjugative interactions.
在溶液中，对氨基酸的构象分析很少，因为这些化合物在这些介质中呈现出双极两性离子结构((+)H3NCHRCOO(-))。此外，在文献中，分子内氢键被归类为唯一控制氨基酸构象行为的相互作用。在本工作中，我们通过(1)H NMR 和红外光谱以及理论计算，研究了不同溶剂中苯丙氨酸和酪氨酸甲酯的构象。实验和理论结果均一致，表明苯丙氨酸和酪氨酸甲酯的构象行为相似，由空间和超共轭相互作用的相互作用决定。
