Download Building Protein Models

Building Protein Models
This is an activity to help you understand primary and secondary structure of proteins.
1. Building the primary structure of a polypeptide.
a. Using one pipe cleaner, construct a polypeptide using 8 plastic beads to represent
amino acids.
b. List the colors in order and the corresponding amino acids in the primary structure.
Amino Acid Key
Glycine
Alanine
Serine
Cysteine
Valine
Leucine
Lysine
Proline
Arginine
Histidine
Bead Color
Black
Orange
White
Dark blue
Light blue
Green
Lavender
Red
Yellow
Pink
Amino Acid
1
2
3
4
5
6
7
8
c. Compare your primary structure to that of your neighbor. Is it exactly the same?
d. Would both of these small polypeptides form the same shape and have the same
function?
2. Secondary Structure - the
- (Alpha) Helix
a. Take another pipe cleaner. Select four pink beads and eight other beads. Build a
primary structure starting and ending with pink beads. Space the beads evenly along
the pipe cleaner.
b. Twist the pipe cleaner into a coil so that all the pink beads are lined up. Imagine
hydrogen bonds between the amino acids represented by the pink beads, holding the
coil shape. Refer to the figure on the next page.
QuickTime™ and a
decompressor
are needed to see this picture.
3. Constructing a ß- (beta) Pleated Sheet
a. Take a pipe cleaner and bend it into a U. Be sure the ends are even with each other.
b. Fold the arms of the pipe cleaner into pleats. Use the figure of the ß- pleated sheet
above as an example.
c. Use the short pieces of pipe cleaner to represent hydrogen bonds between the parallel
arms of the polypeptide.