Amino Acid Tutor

The buttons below will generate a computer image of either a generic amino acid or one of the twenty amino acids found in proteins.

Each amino acid is shown as it exists in a protein. Therefore, while a free amino acid has a carboxylic acid group (-COOH), an amino acid in a protein has a carbonyl group (-CO). The other oxygen is released during peptide bond formation to produce water.

Note also that no hydrogens are displayed in these computer-generated images*. Hydrogens are too small to see by standard x-ray crystallography, therefore they are commonly omitted from structure files.

* Hydrogen atoms are not displayed, except in the case of glycine, whose sidechain consists of a single hydrogen atom.

The standard chemical drawing of each amino acid is shown along with the 3D structure.

You can rotate the image by clicking on the screen and dragging your mouse.

Generic Amino Acid within a Polypeptide
ALA
ARG
ASN
ASP
CYS
GLN
GLU
GLY
HIS
ILE
LEU
LYS
MET
PHE
PRO
SER
THR
TRP
TYR
VAL