Introduction to Amino Acid Selector

The selection forms above each frame let you view each of the 20 amino acids using the Chemscape Chime Plug-in. See the CMU Chime Features page, for a short demonstration on how this plug-in is used with the molecular models shown here.

The amino acids appear first in the Sticks display format with CPK coloring and their side chains (or R-groups) pointing down. These initial images can be changed by using the Chime menu selections (click-and-hold within the image area). The buttons in each frame highlight side chain functional groups, overall dimensions, and side chain polarity. (An explanation of the colors used is in the upper frame.) The "Reset" button will return the display to the starting colors and orientation.

The side-by-side format of this page allows you to compare and contrast the different side-chain features.
Additional information for each amino acid is included below the image in each display frame. (Click on the one-letter code for each.)
Some suggestions for pairs of amino acids to compare:

• Alanine with any other, for differences in R-groups;
• Aspartate with asparagine, for similarities;
• Leucine with isoleucine, for similarities.
• etc.

When you are familiar with the amino acid structures, test your knowledge with the Amino Acid Identification Quiz linked in the upper frame.

The last six entries in the selection lists are peptides. In addition to highlighting features of the peptide bond, these models serve as a review of amino acid side-chain structures. Hydrogen atoms have been omitted from the peptide structures for clarity.

NETSCAPE navigation tips:

• To go back to any image you have already seen, click-and-hold in the current frame and choose "Back". (Choosing "Back" from the "Go" menu list will take you to the last URL you visited; but do come back!)
• An appropriate window size for this page is about eight or nine inches. The frames can be resized by placing the mouse on the borders and dragging.
• If a change in the selection form does not result in a new image from this page, check to see that JavaScript has not been "disabled" (choose "Network preferences..." and then "Languages" under the Netscape Options menu).

Back to Molecular Models for Biochemistry at CMU.

Dr. William McClure
wm0p@andrew.cmu.edu.
Department of Biological Sciences
Carnegie Mellon University
Pittsburgh, PA 15213