1. Lack of rotation around the bond: The peptide bond has a partial double-bond character- that is; it is shorter than a single bond and is therefore rigid and planar. This prevents free rotation around the bond between the carbonyl carbon and the nitrogen of the peptide bond. However the bonds between the α-amino or α-carboxyl groups can be freely rotated and thus allow the polypeptide chain to assume a variety of possible configurations.
2. Trans configuration: The peptide bond is generally a Trans bond (instead of cis), in large part because of steric interference on the R-groups when in the cis position.
Uncharged but polar: Like all amides linkages, -C=0 and –NH groups of the peptide bond neither accept nor give off protons over the pH range of 2 or 12. Thus, the charged groups present in the polypeptides consist solely of the N-terminal α-amino group, the C-terminal α-carboxyl group, and any ionized groups present in the side chains of the constituent amino acids. [NOTE: -C=O and –NH groups of the peptide bond are polar and are involved in hydrogen bongs, for example in α-helices and β-sheet structures]