A Theoretical Study of <i>β</i>-Amino Acid Conformational Energies and Solvent Effect

Abstract

The conformations of four β-amino acids in a model peptide environment were investigated using Hartree-Fock (HF) and density functional theory (DFT) methods in gas phase and with solvation. Initial structures were obtained by varying dihedral angles in increments of 45˚ in the range 0˚ -360˚. Stable geometries were optimized at both levels of theory with the correlation consistent double-zeta basis set with polarization functions (cc-pVDZ). The results suggest that solvation generally stabilizes the conformations relative to the gas phase and that intramolecular hydrogen bonding may play an important role in the stability of the conformations. The β 3 structures, in which the R-group of the amino acid is located on the carbon atom next to the N-terminus, are somewhat more stable relative to each other than the β 2 structures which have the R-group on the carbon next to the carbonyl.

π‐π stacking interactions mediate molecular recognition between arginine and tryptophan containing peptides derived from human islet polypeptide

“…This approach works as we are particularly interested in the trends of the peak shifts and are not assigning absolute peak positions. Previous DFT‐based Raman studies have exploited the use of simpler model compounds, like for instance arginine and tryptophan, to investigate perturbations of specific functional groups found on or near peptides and proteins 22,37,38 …”

“…Previous DFT-based Raman studies have exploited the use of simpler model compounds, like for instance arginine and tryptophan, to investigate perturbations of specific functional groups found on or near peptides and proteins. 22,37,38…”