Peptide models XXIX. cis?trans Isomerism of peptide bonds: ab initio study on small peptide model compound; the 3D-Ramachandran map of formylglycinamide

H.A.BALDONI; G.ZAMARBIDE; E.A.JAUREGUI; O FARKAS; A. PERCZEL; S SALPIETRO; ENRIZ R.D.

JOURNAL OF MOLECULAR STRUCTURE THEOCHEM

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2000 vol. 500 p. 97 - 111

0166-1280

Thermodynamic separations for cis and trans-amides and formylglycinamide range from 0.00 to 4.77 kcal/mol as computed at various levels of theory. The barriers for trans!cis-isomerization, for the same set of compounds, computed at various levels of theory, were found between 15.69 and 22.67 kcal/mol. The cis- and trans-Ramachandran maps of formylglycinamide are compared and the topology of the ab initio 3D-Ramachandran map is presented for the first time.