This serves as a good example of the pattern I described: something is discovered; half the people try to figure out how it works; the other half try to figure out what they can do with it. This is the initial discovery that made all of biotechnology possible in the first place.
The image above comes from Wikipedia's entry on the enzyme EcoRI.
The DNA is in orange at the top. The rest is the protein.
Please also check out a blog written by a friend and colleague of mine, David Goodsell. The blog is called "molecule of the month" and there is a link to it above. Here is the restriction enzyme blog.