Ab initio SCF calculations on low-energy conformers of N-acetylglycylglycine N'-methylamide

摘要: Results from ab initio SCF calculations with a 3-21G and double-ξ plus polarization (DZP) basis set on six low-energy conformations of N-acetylglycylglycine N'-methylamide (diglycine diamide) are reported. In addition, MP2 energies for DZP-optimized geometries also given. The lowest energy conformation found at the DZP level is type II β-turn dihedral angles close to reported «ideal» values. This contrasts results which yield two C 7 -turns as structure. geometric differences between 3-21G- DZP-minimized conformers very small except conformer