Comprehensive conformational analysis of N-acetyl-L-isoleucine-N-methylamide: an ab initio study

CALAZA, FLORENCIA C.; RIGO, MARIA V.; RINALDONI, ANA N.; MASMAN, MARCELO F.; KOO, JOSEPH C. P. ; RODRIGUEZ, ANA M.; ENRIZ, RICARDO D.

JOURNAL OF MOLECULAR STRUCTURE THEOCHEM

ELSEVIER SCIENCE BV

Año: 2003 vol. 634 p. 201 - 213

0166-1280

A conformational study on N-acetyl-L-isoleucine-N-methylamide was carried out using ab initio (RHF/3-21G and RHF/631G(d)) calculations. All backbone and side-chain conformations in this compound were explored. N-acethyl-L-isoleucine-N-methylamide displayed a significant molecular flexibility. Also a different conformational behaviour was obtained for this amino acid residue in comparison with other amino acids possessing shorter apolar side-chains. These results can be attributed, at least in part, to the side-chain/backbone interactions, which are stabilizing the low-energy conformations in this molecule.