Protein 1

Table of Contents
Biomolecules Gateway Page
Jmol Tutorial

In this module:

Amino Acids
Hydrophobic and Polar Amino Acids
Acidic and Basic Amino Acids
Peptide Bonds
Planarity of Peptide Bonds
Protein Sequences
Sickle Cell Anemia

Planarity of Peptide Bonds

Interestingly, peptide bonds have a second resonance form, as demonstrated below. This means that the peptide bond (the C=O and N-H) all reside in a single plane. Thus, there is no rotation around the bond.

Click on the structure below to switch the resonance forms of the peptide bond.

The structure at the right shows a peptide bond between the amino acids valine (Val) and serine (Ser). The amino acids are taken from the crystal structure of hemoglobin (αVal132 and αSer133). The four atoms that are part of the peptide bond are shown as larger spacefilling models. Because of the partial double bond between the α carbon and the amine nitrogen, no rotation is possible around that bond.

Planarity of Peptide Bonds