Example #1: Collagen - A Fibrous Protein
Collagen is an example of a fibrous protein. Fibrous proteins
differ from globular proteins in that they are insoluble in water
(due to hydrophobic sidechains) and function primarily as structural components.
Example #2: An Enzyme - Penicillopepsin (an Acid Proteinase)
The following enzyme is a proteinase, i.e., its function is to
break down proteins. Its more general enzyme classification is hydrolase.
In the structure shown below use the "Zoom In" button to observe
how the substrate fits into the active site and how it is held in place by
hydrogen bonds. (It will be easier
to see the hydrogen bonding if the spacefilling is turned off.)