Dipeptide structures along whole Ramachandran plot

Relative energies and structures along the whole Ramachandran plot were obtained from quantum chemical calculations for Alanine dipeptide (AcAlaNH2). The relaxed two-dimensional (2D) scan has been computed at the B3LYP-D3 level with double-zeta plus polarisation SNSD basis set by varying the Psi and Phi dihedral angles from -180 to 180°, in 10° intervals. In the relaxed 2D scan all other structural parameters have been fully optimized. Dataset reports Energies and Cartesian coordinates for each of 1369 points in 2D scan. These quantum mechanical computations performed using the small dipeptide molecular model match well Ramachandran plot with energetically allowed large basin corresponding to the α-helix and β-sheet and predicted very accurate structural parameters within the local arrangement for unusual high-energy conformations.