N-acetyi-L-aspartic acid-N′-methylamide with side-chain orientation capable of external hydrogen bonding: Backbone and side-chain folding, studied at the DFT level of quantum theory

J. C.P. Koo, G. A. Chass, A. Perczel, Ö Farkas, A. Varro, L. L. Torday, J. Gy Papp, I. G. Csizmadia

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In this study, we generated and analyzed the side-chain conformational potential energy hypersurfaces for each of the nine possible backbone conformers for N-acetyl-L-aspartic acid-N' methylamide. We found a total of 27 out of the 81 possible conformers optimized at the B3LYP/6-31G(d) level of theory. The relative energies, as well as the stabilization energies exerted by the side-chain on the backbone, have been calculated for each of the 27 optimized conformers at this level of theory. Various backbone-backbone (N-H⋯O=C) and backbone-side-chain (N-H⋯O=C; N H⋯OH) hydrogen bonds were analyzed. The appearance of the notoriously absent εL backbone conformer may be attributed to such side-chain-backbone (SC/BB) and backbone-backbone (BB/BB) hydrogen bonds.

Original languageEnglish
Pages (from-to)499-511
Number of pages13
JournalEuropean Physical Journal D
Issue number3
Publication statusPublished - Sep 1 2002


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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