Author(s)

Victor F. Waingeh^1*, Felix N. Ngassa^2*, Jie Song³

¹School of Natural Sciences, Indiana University Southeast, New Albany, IN, USA.
²Department of Chemistry, Grand Valley State University, Allendale, MI, USA.
³Department of Chemistry and Biochemistry, University of Michigan-Flint, Flint, MI, USA.

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 β³ 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 β² structures which have the R-group on the carbon next to the carbonyl.

Density Functional Theory, β-Amino Acids, Conformational Search

Waingeh, V. , Ngassa, F. and Song, J. (2015) A Theoretical Study of β-Amino Acid Conformational Energies and Solvent Effect. Open Journal of Physical Chemistry, 5, 122-131. doi: 10.4236/ojpc.2015.54013.