An exploratory ab initio study of the full conformational space of N-acetyl-L-cysteine-N-methylamide

ZAMORA, M.A.; BALDONI, H.A.; BOMBASARO, J.A.; MAK, M.L.; PERCZEL, A.; FARKAS, O.; ENRIZ, R.D.

JOURNAL OF MOLECULAR STRUCTURE THEOCHEM

ELSEVIER SCIENCE BV

Año: 2001 vol. 540 p. 271 - 283

0166-1280

The full conformational space of N-acetyl-L-cysteine-N-methylamide was explored by ab initio MO computations. On the Ramachandran hypersurface of four independent variables E = E(φ,ψ,χ1,χ2), 47 conformers were located instead of the expected 34 = 81 stable structures. The relative stabilities of the various conformers were analyzed in terms of side-chain-backbone interactions covering both hydrogen bonding and charge-transfer types. The stabilization energies exerted by the side-chain of cysteine on the backbone were compared to those of other amino acids. © 2001 Elsevier Science B.V.