Eur. Phys. J. D 20, 499-511 (2002)
https://doi.org/10.1140/epjd/e2002-00148-5

N-acetyl-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

¹ Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6
² Velocet R & D, 210 Dundas St. West, Suite 810, Toronto, Ontario, Canada M5G 2E8
³ Department of Organic Chemistry, Eotvos University, 1117 Budapest, Hungary
⁴ Department of Pharmacology and Pharmacotherapy, Szeged University, Dom ter 12, 6701 Szeged, Hungary
⁵ Division of Cardiovascular Pharmacology, Hungarian Academy of Sciences and Szeged University, Dom ter 12, 6701 Szeged, Hungary

Corresponding authors: ^a joseph.koo@utoronto.ca - ^b gchass@fixy.org - ^c perczel@para.chem.elite.hu - ^d farkas@organ.elite.hu - ^e pyro@phcol.szote.u-szeged.hu - ^f papp@phcol.szote.u-szeged.hu - ^g icsizmad@alchemy.chem.utoronto.ca

Received: 10 February 2002
Published online: 13 September 2002

Abstract

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–HO=C) and backbone-side-chain (N–HO=C; N–HOH) hydrogen bonds were analyzed. The appearance of the notoriously absent backbone conformer may be attributed to such side-chain-backbone (SC/BB) and backbone-backbone (BB/BB) hydrogen bonds.